/////////////////////////////////////////////////////////////// THIS FILE NOW HAS ALL THE CIRCULARS EVER WRITTEN FOR SGR 1806-20: First (in GCN record era) outburst: /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 775 SUBJECT: SGR 1806-20 burst activity DATE: 00/08/18 22:57:26 GMT FROM: Peter Woods at UAH/MSFC E. Gogus (UAH), P.M. Woods, C. Kouveliotou (USRA), and J. Swank (GSFC) report on behalf of a larger collaboration: During an RXTE PCA observation from an ongoing ~weekly SGR monitoring campaign, we have detected a recurrence of burst activity from SGR 1806-20. During two 5 ks observations of the source on 12 August 2000, we detected two brief, intense bursts. The brighter of the two bursts reached a peak flux (4ms) of ~5e-7 ergs/cm^2 s (>25keV). Further observations are encouraged. This message is citeable. /////////////////////////////////////////////////////////////// Second outburst: /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1068 SUBJECT: SGR1806-20: Localization by HETE DATE: 01/06/18 21:45:45 GMT FROM: George Ricker at MIT SGR1806-20: Localization by HETE G. Ricker, D. Lamb, and S. Woosley on behalf of the HETE Science Team; R. Vanderspek, G. Crew, J. Doty, G. Monnelly, J. Villasenor; N. Butler, T. Cline, J.G. Jernigan, A. Levine, F. Martel, G. Pizzichini, and G. Prigozhin, on behalf of the HETE Operations and HETE Optical-SXC Teams; N. Kawai, M. Matsuoka, Y. Shirasaki, T. Tamagawa, A. Yoshida, E. Fenimore, M. Galassi, and C. Graziani, on behalf of the HETE WXM Team; J-L Atteia, M. Boer, J-F Olive, J-P Dezalay, and K. Hurley on behalf of the HETE FREGATE Team; write: At 19:42:49 UT on 18 June, the HETE FREGATE and WXM instruments detected and localized burst emission from the vicinity of SGR1806-20, a soft gamma-ray repeater. This event may indicate the onset of a new period of activity by this source. The coordinates (J2000) of the burst source were: R.A. = 272.0265 deg. Dec. = -20.2743 deg The error circle for the localization is 36 arcmin in radius. SGR1806-20 lies 11.8 arcmin from the HETE position. [Another galactic X-ray source, GX9+1, lies 100 arcmin from the HETE position.] The burst duration in the 8-40 keV band was <300 ms. A total of 864 counts were detected during that interval, corresponding to a flux of >10 times Crab. Follow-up observations of this transient are encouraged. Additional information on this burst detection (including light curves), as well as for the HETE mission, will be available at: http://space.mit.edu/HETE/ Acronyms: HETE=High Energy Transient Explorer FREGATE=French Gamma Ray Telescope WXM=Wide Field X-ray Monitor SXC=Soft X-ray Camera This message is citeable. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1070 SUBJECT: SGR1806-20: A Second, Intense Burst Localized by HETE DATE: 01/06/23 18:21:44 GMT FROM: George Ricker at MIT SGR1806-20: A Second, Intense Burst Localized by HETE G. Ricker, D. Lamb, and S. Woosley on behalf of the HETE Science Team; R. Vanderspek, G. Crew, J. Doty, G. Monnelly, J. Villasenor; N. Butler, T. Cline, J.G. Jernigan, A. Levine, F. Martel, E. Morgan, G. Pizzichini, and G. Prigozhin, on behalf of the HETE Operations and HETE Optical-SXC Teams; N. Kawai, M. Matsuoka, Y. Shirasaki, T. Tamagawa, K.Torii, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi, and C. Graziani, on behalf of the HETE WXM Team; J-L Atteia, M. Boer, J-F Olive, J-P Dezalay, and K. Hurley on behalf of the HETE FREGATE Team; write: At 15:54:53.123 UT on 23 June, the HETE FREGATE and WXM instruments detected and localized an intense burst from SGR1806-20, a soft gamma-ray repeater. This event, disseminated in near real time as a GCN Alert (HETE BID_1566; see http://gcn.gsfc.nasa.gov/gcn/hete_grbs.html), is the second burst localized from this source in the past week. (The first burst was reported in GCN Circular #1068). The coordinates (J2000) of the 23 June burst are: R.A. = 272.1460 deg. (18h08m35s.02) Dec. = -20.3658 deg. (-20:21:56) The error circle for this localization is 6 arcmin in radius. SGR1806-20 lies 3.1 arcmin from the HETE position. The burst duration in the 8-40 keV band was ~200 ms, comprised of two peaks each <100ms in duration. A total of 2250 counts were detected during that interval, corresponding to a fluence of ~4 x 10-7 ergs cm-2 . The peak flux was >6 x 10-6 ergs cm-2 s (ie >200 x Crab flux). Follow-up observations of this transient are encouraged. Additional information on this burst detection (including light curves), as well as for the HETE mission, will be available at: http://space.mit.edu/HETE/ Acronyms: HETE=High Energy Transient Explorer FREGATE=French Gamma Ray Telescope WXM=Wide Field X-ray Monitor SXC=Soft X-ray Camera This message is citeable. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1072 SUBJECT: Possible burst from SGR1806-20 DATE: 01/06/26 23:21:40 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley, on behalf of the Ulysses GRB team, reports: In addition to observing the burst from SGR1806-20 on 2001 June 23 at 57293 s UT (GCN 1070), Ulysses observed a later event whose origin is likely to be this same SGR. This burst would have had an Earth-crossing time of 61056.8 s. Its duration was ~0.032 s, and its 25-100 keV fluence was ~2x10^-7 erg/cm^2. It had a peak flux over 0.032 s of ~6x10^-6 erg/cm^2 s. To our knowledge, no other instrument observed this event so we cannot be absolutely certain of its origin, but based on its time history and proximity in time to the previous burst, its origin is likely to be SGR1806-20, rather than SGR1900+14 (GCN 1071). /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1089 SUBJECT: Probable SGR or Short Duration GRB Detected by HETE DATE: 01/08/22 21:48:53 GMT FROM: George Ricker at MIT Probable SGR or Short Duration GRB Detected by HETE G. Ricker, D. Lamb, and S. Woosley on behalf of the HETE Science Team; R. Vanderspek, G. Crew, J. Doty, G. Monnelly, J. Villasenor, N. Butler, T. Cline, J.G. Jernigan, A. Levine, F. Martel, E. Morgan, G. Prigozhin, J. Braga, R. Manchanda, and G. Pizzichini, on behalf of the HETE Operations and HETE Optical-SXC Teams; N. Kawai, M. Matsuoka, Y. Shirasaki, T. Tamagawa, K. Torii, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi, T. Donaghy, and C. Graziani, on behalf of the HETE WXM Team; J-L Atteia, M. Boer, J-F Olive, J-P Dezalay, and K. Hurley on behalf of the HETE FREGATE Team; write: At 05:06:30.61 UTC (18390.61 s UT) on 22 August, the HETE FREGATE instrument detected a short, intense burst from a probable soft gamma-ray repeater or (less likely) a short duration GRB. This event was promptly distributed as a GCN Notice (HETE BID_1715). No signal was detected in the WXM, indicating that the event was likely to be >40 degrees from the anti-sun direction. For the current HETE pointing direction, SGR1900+14 is about 48 degrees off the boresight, while SGR1806-20 is about 56 degrees off the boresight, so that either could be a candidate. The burst duration in the 8-85 keV band was ~200 ms. A total of 500 counts were detected during that interval, corresponding to a fluence of ~9 x 10-8 ergs cm-2 . The peak flux was >2 x 10-6 ergs cm-2 s-1 (ie >50 x Crab flux) over a duration of 30 ms. A search for this event in the archives of other GRB instruments is encouraged. This message is citeable. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1129 SUBJECT: Optical observation of SGR 1806-20 at the 6-m SAO telescope DATE: 01/11/03 19:18:24 GMT FROM: Alexei Pozanenko at IKI, Moscow G. Beskin, V. Debur, A. Panferov, I. Panferova, V. Plokhotnichenko (SAO), A. Pozanenko, (IKI), M. Boer, J.L. Atteia, A. Klotz (CESR/CNRS), G. Ricker (MIT) We have observed SGR 1806-20 during its probable gamma-ray activity (GCN 1068, 1089). Observations were performed with 6-meter telescope of Special Astrophysical Observatory equipped with the high time resolution Multichannel Panoramic Photometer-Polarimeter and MANIA registration system. Observations of a 1 arcmin diameter area covered IPN position of the object (K.Hurley, ApJ, 523, L37, 1999) were carried out in B band on June, 20th and August, 22nd. The start time on June, 20 is UT 19:58 (2 days after HETE trigger), and start time in August, 22 is UT 20:31 (16 hours after HETE trigger). Accumulation time is 4500s and 800s, respectively. The arrival time of each photon was measured with an accuracy of 1 mcsec, and the spatial resolution reached 0.2 arcsec. No variable emission in the range 2 mcsec - 1s was found in 300 sq.arcsec region centered in IPN source position. Three sigma upper limits for the relative power (in respect to background) of the variable radiation component in the form of triangle-like flares with a filling factor of 0.1 are: 35% at 5 mcsec, 10% at 0.5 ms, 5% at 0.01 s and 1% at 1s. Analysis of entire image area for variable emission is in progress. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1222 SUBJECT: IPN observations of SGR1806-20 DATE: 02/01/25 20:48:02 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley, on behalf of the Ulysses GRB team, and C. Guidorzi, E. Montanari, F. Frontera, and M. Feroci, on behalf of the BeppoSAX GRBM team, report: Ulysses and BeppoSAX have detected a series of short duration bursts which appear to originate from SGR1806-20: DATE TIME ULYSSES BEPPOSAX ____ ____ _______ ________ 020117 81678* YES IN SAA AND EARTH-BLOCKED 020118 71671 YES YES 020122 38418* YES NO DATA *TIME AT ULYSSES, WHICH WAS ABOUT 1250 LIGHT-SECONDS FROM EARTH; EARTH-CROSSING TIME FOR SGR1806 IS ABOUT 107 S LATER The only burst which could be triangulated was the one on January 18, and its position agrees with that of SGR1806-20. The burst on January 22 was particularly intense. If all of these events are indeed from SGR1806-20, this may signal a resurgence of activity from this source. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1233 SUBJECT: IPN detection of further activity from SGR1806-20 DATE: 02/01/29 00:34:27 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley, on behalf of the Ulysses GRB team, E. Mazets and S. Golenetskii, on behalf of the Konus-Wind GRB team, and C. Guidorzi, E. Montanari, F. Frontera, and M. Feroci, on behalf of the BeppoSAX GRBM team, report: The IPN continues to detect activity which is probably from SGR1806-20. The updated event list is now: DATE TIME ULYSSES BEPPOSAX KONUS ____ ____ _______ ________ _____ 020117 81788 YES IN SAA WEAK RESPONSE 020118 71671 YES YES YES 020122 38499 YES NO DATA YES 020124 79251* YES 020125 36444* YES *TIME AT ULYSSES, WHICH WAS ABOUT 1250 LIGHT-SECONDS FROM EARTH; EARTH-CROSSING TIME FOR SGR1806 IS ABOUT 75 S LATER The bursts on the 17th, 18th, and 22nd have all been triangulated to annuli which are consistent with the position of SGR1806. The bursts on the 24th and 25th are definitely SGR-like, in that their durations are ~30 ms; there are too few photons in the Ulysses data to determine their spectra, however. We are searching for confirmation of them in the GRBM and KONUS data, which will allow triangulation. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1391 SUBJECT: IPN triangulation of a burst from SGR1806-20 DATE: 02/05/16 00:18:36 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley, on behalf of the Ulysses GRB team, and D. Smith, R. Lin, J. McTiernan, R. Schwartz, C. Wigger, W. Hajdas, and A. Zehnder, on behalf of the RHESSI GRB team, report: Ulysses and RHESSI observed a burst on May 15 at 01:26:41 UT with ~20 ms duration. Triangulation gives an annulus which is consistent with the position of SGR1806-20. Ulysses has in addition observed numerous short events over the past several days. Although none could be triangulated, this may suggest that SGR1806-20 is entering a new period of activity. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1396 SUBJECT: IPN detection of possible bursts from SGR1806-20 DATE: 02/05/27 23:19:13 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley, on behalf of the Ulysses GRB team, E. Mazets and S. Golenetskii, on behalf of the Konus-Wind GRB team, and T. Cline, on behalf of the Ulysses and Konus teams, report: Two short bursts were detected on May 25 which, due to their proximity in time to an earlier burst from SGR1806-20 (see GCN 1391), may also be from this SGR. The first was at ~16014 s and was observed by Konus-Wind; the second was detected by Ulysses and was at 43615 s (Ulysses time; the spacecraft was ~1850 light-seconds from Earth). If the second event came from SGR1806-20, its Earth-crossing time would have been ~1047 s earlier, or ~42568 s. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1726 SUBJECT: IPN detection of renewed activity from SGR1806-20 DATE: 02/12/07 20:31:06 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley, on behalf of the Ulysses GRB team, E. Mazets and S. Golenetskii, on behalf of the Konus-Wind GRB team, and T. Cline, on behalf of the Ulysses and Konus GRB teams, report: Ulysses has observed 5 short, intense SGR-like bursts on December 5 and 6. So far, one of these events has also been reported by Konus-Wind, and the center line of its triangulation annulus passes ~10" from the position of SGR1806-20, and >5 degrees from that of SGR1900+14. We conclude that this burst indeed originates from SGR1806-20. As there is a hint of continuing activity from SGR1900+14, we cannot at this point be certain of the origin of the other events, but will attempt to determine this as soon as possible. The times of these events were: December 5, 2002: 02828 s * 12925 s * 32992 s ** 72064 s * December 6, 2002: 63291 s * * crossing time at Ulysses; subtract ~418 s to get Earth-crossing time if the source was SGR1806-20 ** event also observed by Konus; this is the Earth-crossing time /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1764 SUBJECT: IPN detection of continued activity from SGR1806-20 DATE: 02/12/17 21:58:18 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses GRB team, and V. Pal'shin, E. Mazets, and S. Golenetskii, on behalf of the Helicon- Coronas GRB team, report: Ulysses and Helicon observed this burst at 40754 seconds. As observed by Ulysses, it had a duration of approximately 0.25 seconds, a 25-100 keV fluence of approximately 6.4E-06 erg/cm2, and a peak flux of approximately 7.4E-06 erg/cm2 s over 0.25 seconds. We have triangulated it to a preliminary annulus centered at RA, Decl(2000)= 3.003, -36.081 degrees, whose radius is 78.796 +/- 0.034 degrees (3 sigma ). As the center line of this annulus passes within 14" of the position of SGR1806-20, we conclude that it was the source of this burst. Prior to this, the last confirmed burst from this SGR was on December 5 (GCN 1726). /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2283 SUBJECT: HETE detection of burst from SGR1806-20 DATE: 03/06/16 18:22:18 GMT FROM: Roland Vanderspek at MIT K. Hurley, J-L. Atteia, N. Kawai, D. Lamb, G. Ricker, and S. Woosley on behalf of the HETE Science Team; C. Barraud, M. Boer, J-F Olive, and J-P Dezalay on behalf of the HETE FREGATE Team; N. Butler, G. Crew, J. Doty, G. Prigozhin, R. Vanderspek, J. Villasenor, T. Cline, J. G. Jernigan, A. Levine, F. Martel, E. Morgan, G. Monnelly, G. Azzibrouck, J. Braga, R. Manchanda, and G. Pizzichini, on behalf of the HETE Operations and HETE Optical-SXC Teams; M. Suzuki, C. Graziani, Y. Shirasaki, T. Donaghy, M. Matsuoka, K. Torii, T. Tamagawa, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi, Y. Nakagawa, R. Satoh, Y. Urata, T. Yamazaki and Y. Yamamoto, on behalf of the HETE WXM Team report: HETE Trigger H2734, detected at 04:14:29 UT on 9 June 2003, was due to a short burst from SGR1806-20. This burst had a duration of ~100 ms and a 30-100 keV fluence of 6 x 10^-8 erg/cm2. The position was not circulated automatically because the spacecraft aspect had not yet been determined. This detection may indicate the onset of a new period of activity for this SGR. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2297 SUBJECT: IPN detection of renewed activity from SGR1806-20 DATE: 03/07/14 18:51:10 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses and HETE GRB teams, D. M. Smith, R. P. Lin, J. McTiernan, R. Schwartz, C. Wigger, W. Hajdas, and A. Zehnder, on behalf of the RHESSI GRB team, A. von Kienlin, G. Lichti, and A. Rau, on behalf of the INTEGRAL SPI-ACS GRB team, and G. Ricker, J-L Atteia, N. Kawai, D. Lamb, S. Woosley, J. Doty, R. Vanderspek, J. Villasenor, G. Crew, G. Monnelly, N. Butler, J.G. Jernigan, A. Levine, F. Martel, E. Morgan, G. Prigozhin, J. Braga, R. Manchanda, G. Pizzichini, Y. Shirasaki, C. Graziani, M. Matsuoka, T. Tamagawa, K. Torii, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi, T. Tavenner, T. Donaghy, M. Boer, J-F Olive, and J-P Dezalay, on behalf of the HETE GRB team, report: Ulysses, INTEGRAL (SPI-ACS), RHESSI, and HETE have observed two events whose arrival directions are consistent with that of SGR1806-20: DATE UT ANNULUS ANNULUS ANNULUS deltaR DISTANCE DURATION PEAK FLUX FLUENCE SPACECRAFT S. RA(2000) DEC(2000) RADIUS (3 SIGMA) DEG. S. erg/cm2s erg/cm2 030712 76693.0 335.440 -27.794 57.625 0.017 0.003 0.180 5E-6 4E-6 ULYSSES, RHESSI, INTEGRAL 030713 77470.8 335.566 -27.667 57.749 0.017 0.0001 0.032 1E-6 1E-7 ULYSSES, HETE(2763) The annulus half-width is deltaR; distance is the angular distance between the centerline of the annulus and the position of SGR1806-20; duration is the duration as observed by Ulysses; peak fluxes and fluences are as observed by Ulysses, and are over 0.03125 s, and 25-100 keV. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2306 SUBJECT: RXTE PCA Observations of SGR1806-20 Region DATE: 03/07/18 02:53:20 GMT FROM: Craig Markwardt at GSFC RXTE PCA Observations of SGR 1806-20 Region A. Ibrahim (GWU/GSFC), C. Markwardt (UMD/GSFC), J. Swank (GSFC), K. Hurley (UCB), T. Cline (GSFC), & W. Parke (GWU) Report: In response to the burst activity reported by IPN on Jul 14 (GCN 2297), we pointed the RXTE PCA at the position of SGR 1806-20 on Jul 15, 11:35-12:20 UT. A 0.4 mCrab pulsed flux was detected with a period of 5.54 s +/- 0.01 s. The PCA saw 3.5 mCrab total flux, but as much as half is due to Galactic ridge emission in the field of view, so that the pulsed fraction could exceed 20%. The large difference between the pulse period and the last observed pulse period of SGR 1806-20 (Woods et al. 2002, ApJ, 576, 381) suggests that a new pulsar is present. There are no known pulsars with that period in the 1.2 deg radius field of view of the PCA and we can rule out the nearby candidate SGR 1801-23 (Cline et al. 2000, ApJ, 531, 407). If the new pulsar were responsible for the recent bursts, there would be three SGRs in a small region. However it is possible that both SGR 1806-20 and another pulsar are active simultaneously. PCA scanning observations are planned. This message is citeable. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2307 SUBJECT: IPN triangulation of GRB030717 (annulus) DATE: 03/07/18 18:38:41 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses GRB team, and A. von Kienlin, G. Lichti, and A. Rau, on behalf of the INTEGRAL SPI-ACS GRB team, report: Ulysses and INTEGRAL (SPI-ACS) observed this burst at 74964 s. As observed by Ulysses, it had a duration of approximately 0.06 seconds, a 25-100 keV fluence of approximately 3E-7 erg/cm2, and a peak flux of approximately 7E-06 erg/cm2 s over 0.03125 seconds. We have triangulated it to a preliminary annulus centered at RA, Decl(2000)= 336.064, -27.164 degrees, whose radius is 38.543 +/- 0.020 degrees (3 sigma). The Ulysses and INTEGRAL time histories are identical in duration, but otherwise rather featureless. Although the annulus does not pass through any of the known SGRs, given the current activity of SGR1806-20, we cannot exclude the possibility that the Ulysses response is due to SGR1806-20, and occurs by chance within the +/-2900 s Ulysses crossing window, while the INTEGRAL response is due to a short/hard GRB. This annulus may be constrained and/or improved but it is not known at this point whether this event was observed by Mars Odyssey, and thus whether a small error box can be derived for it. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2308 SUBJECT: H2768, H2770, and H2771: Three Bursts from SGR1806-20 DATE: 03/07/19 04:37:36 GMT FROM: George Ricker at MIT H2768, H2770, and H2771: Three Bursts from SGR1806-20 K. Hurley, J-L. Atteia, N. Kawai, D. Lamb, G. Ricker, and S. Woosley on behalf of the HETE Science Team; C. Barraud, M. Boer, J-F Olive, and J-P Dezalay on behalf of the HETE FREGATE Team; N. Butler, G. Crew, J. Doty, A. Dullighan, G. Prigozhin, R. Vanderspek, J. Villasenor, T. Cline, J. G. Jernigan, A. Levine, F. Martel, E. Morgan, G. Monnelly, G. Azzibrouck, J. Braga, R. Manchanda, and G. Pizzichini, on behalf of the HETE Operations and HETE Optical-SXC Teams; T. Tamagawa, M. Suzuki, C. Graziani, Y. Shirasaki, T. Donaghy, M. Matsuoka, K. Torii, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi, Y. Nakagawa, R. Satoh, Y. Urata, T. Yamazaki and Y. Yamamoto, on behalf of the HETE WXM Team; report: At 08:02:20.59 UT on 17 July, the HETE FREGATE and WXM instruments detected and localized H2768, a short duration, soft spectrum burst event from the vicinity of the soft gamma repeater SGR1806-20. The coordinates (J2000) of H2768 derived by the WXM are: R.A. = 271.716 deg Dec. = -20.461 deg The one sigma (statistical) error circle for the localization is 5.2 arcmin in radius. SGR1806-20 lies about 24 arcmin from the HETE position. However, a number of factors combined to produce larger-than-normal systematic errors for H2768. They are related to the fact that H2768 was detected in orbit day, after star camera turnoff. Using reasonable assumptions about the spacecraft drift, the position derived for H2768 is believed to be completely compatible with that of SGR1806-20. At 23:43:12.12 UT on 18 July, a second short duration event (H2770), was detected and localized from the vicinity of SGR1806-20. The duration (t50) of H2770 was 60 +/- 7 ms in the 7-40 keV band. The coordinates (J2000) derived by the WXM are: R.A. = 272.176 deg Dec. = -20.590 deg The localization for H2770 was determined on board HETE by the flight software, and disseminated 7 minutes later. The error circle (90% confidence) for the flight localization is 30 arcmin in radius. SGR1806-20 lies about 10 arcmin from the center of the HETE WXM error circle. Thus, the position derived for H2770 is also fully consistent with that of SGR1806-20. Most recently, at 03:24:15.28 UT on 19 July, a third short duration event (H2771), was detected and localized from the vicinity of SGR1806-20. The duration (t50) of H2771 was 90 +/- 25 ms in the 7-40 keV band. The coordinates (J2000) of H2771 derived by the WXM are: R.A. = 272.241 deg Dec. = -20.626 deg The localization for H2771 was determined on board HETE by the flight software, and disseminated 20 seconds later. The error circle (90% confidence) for the flight localization is 30 arcmin in radius. SGR1806-20 lies about 12 arcmin from the center of the HETE WXM error circle. Thus, the position derived for H2771 is also fully consistent with that of SGR1806-20. Based on the accurate localization and the rapid cadence of these three HETE burst events, we conclude that the soft gamma repeater SGR1806-20 has evidently entered a heightened state of burst activity. This message may be cited. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2309 SUBJECT: SGR 1806-20, submm observations DATE: 03/07/19 05:22:38 GMT FROM: Sylvio Klose at TLS Tautenburg S. Klose (@SEST), B. Stecklum, & H. Linz, Thuringer Landessternwarte Tautenburg, J. Greiner, MPE Garching, report: We observed the field of SGR 1806-20 with the Swedish-ESO Submillimetre Telescope (SEST) at La Silla, Chile, on July 18/19, 0:35 - 2:10 UT. The observations were performed with the SIMBA Imaging Bolometer Array at a wavelength of 1.2mm and started approximately 45 min after an outburst was recorded from SGR 1806 by HETE 2 and ended approximately 1.5 hrs before the next outburst was recorded (Hurley et al., GCN 2308). A superposition of 4 maps (400 x 600 arcsec), 8 min mapping time each, does not reveal any source at the position of the SGR down to a flux density limit of approximately 100 mJy. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2311 SUBJECT: Konus-Wind detection of the bursts from SGR1806-20 region DATE: 03/07/22 13:47:11 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks (all Ioffe Institute), T. Cline (NASA GSFC), and K.Hurley (UCB) on behalf of the Konus-Wind team, report: A short soft burst was detected on 030719 by Konus-Wind starting at 83914.490s UT. The event had a duration of 0.25s, a soft energy spectrum ~ E^(-1)exp(-E/Eo) with Eo = 18.5 +/- 1 keV, fluence of 5x10-6 erg sm-2 and peak flux of 3x10-5 erg cm-2 s-1, evaluated both in 15-300 keV range. Apparently the burst originates from the SGR1806-20 or from its close vicinity in accordance with observations of the burst activity reported in GCN 2306, 2307, and 2308. Two weak soft events were detected by Konus-Wind in the background mode on 030720 at 08:07:12 and 22:34:19. The last event was detected by HETE (H2773). Estimated time delay is consistent with SGR1806-20 position. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2346 SUBJECT: IPN/HETE summary of recent bursts from SGR1806-20 DATE: 03/08/06 20:35:27 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses, HETE, and KONUS GRB teams, S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, and D. Frederiks, on behalf of the Konus-Wind GRB team, G. Ricker, J-L Atteia, N. Kawai, D. Lamb, S. Woosley, J. Doty, R. Vanderspek, J. Villasenor, G. Crew, G. Monnelly, N. Butler, J.G. Jernigan, A. Levine, F. Martel, E. Morgan, G. Prigozhin, J. Braga, R. Manchanda, G. Pizzichini, Y. Shirasaki, C. Graziani, M. Matsuoka, T. Tamagawa, K. Torii, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi, T. Tavenner, T. Donaghy, M. Boer, J-F Olive, and J-P Dezalay, on behalf of the HETE GRB team, A. von Kienlin, G. Lichti, and A. Rau, on behalf of the INTEGRAL SPI-ACS GRB team, and D. M. Smith, R. P. Lin, J. McTiernan, R. Schwartz, C. Wigger, W. Hajdas, and A. Zehnder, on behalf of the RHESSI GRB team, report: The following is a summary of all the known bursts which originated, or are likely to have originated, from SGR1806-20 between July 12 and August 5, 2003. This is based on the IPN and HETE data available to us at this time. In the table below, "LOCALIZED" means either an IPN annulus, a HETE WXM one-dimensional localization, or a HETE WXM two-dimensional localization. In those cases where there is no localization, the bursts are short-duration, soft-spectrum events, all the data for which are consistent with an origin from SGR1806-20. Still other short events have been detected, one as recently as August 5, but their origin remains uncertain at this time. DAY, UT AT EARTH, LOCALIZED? REFERENCE OBSERVED BY JULY SECONDS 2003 _________________________________________________________________________ 12 76693 YES GCN 2297 ULYSSES, RHESSI, INTEGRAL 13 77479 YES GCN 2297 ULYSSES, RHESSI, HETE (2763) 17 28940 YES GCN 2308 HETE (2768) 18 68854 NO HETE 18 85392 YES GCN 2308 HETE (2770) 19 12255 YES GCN 2308 HETE (2771) 19 29227 YES GCN 2311* ULYSSES, KONUS, HETE, RHESSI 19 38889 YES HETE (2772) 19 74588 NO HETE 19 81255 YES GCN 2311* ULYSSES, KONUS, HETE (2773), RHESSI 19 83914 YES GCN 2311 ULYSSES, KONUS, RHESSI 20 29002 NO HETE 21 40289 NO HETE 22 06477 NO HETE (2775) 22 34236 YES HETE (2776), ULYSSES 27 64946 NO HETE (2781) *NOTE TYPO IN THE DATE IN GCN 2311: THE KONUS UNTRIGGERED EVENTS WERE ON THE 19TH, NOT THE 20TH /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2351 SUBJECT: SGR 1808-20 (=H2802): A Possible new SGR DATE: 03/08/15 21:39:10 GMT FROM: Don Lamb at U.Chicago D. Lamb, C. Graziani, Y. Shirasaki, J-L. Atteia, C. Barraud, K. Hurley, G. Crew, N. Kawai, G. Ricker, and S. Woosley on behalf of the HETE Science Team; M. Boer, J-F Olive, and J-P Dezalay on behalf of the HETE FREGATE Team; N. Butler, J. Doty, A. Dullighan, G. Prigozhin, R. Vanderspek, J. Villasenor, T. Cline, J. G. Jernigan, A. Levine, F. Martel, E. Morgan, G. Monnelly, G. Azzibrouck, J. Braga, R. Manchanda, and G. Pizzichini, on behalf of the HETE Operations and HETE Optical-SXC Teams; T. Tamagawa, M. Suzuki, T. Donaghy, M. Matsuoka, K. Torii, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi, Y. Nakagawa, R. Satoh, Y. Urata, T. Yamazaki and Y. Yamamoto, on behalf of the HETE WXM Team; write: At 09:52:03.04 UTC (35523.04 s UT) on 13 Aug 2003, the HETE-2 FREGATE and WXM instruments detected event H2802, an SGR burst. The WXM flight localization was correct and was reported in a GCN Notice at 10:00:17 UT, 8 minutes after the beginning of the burst. The WXM flight localization of the burst was a circle centered at WXM Flight: RA = +18h 08m 07s, Dec = -20d 38' 20" (J2000) , with a 14 arcminute error radius, which was marginally inconsistent with a burst from SGR 1806-20 and hence the Notice contained no flag stating that the source matches a known X-ray source. Ground analysis of the WXM data produced a localization that was reported in a GCN Notice at 11:55:09 UT. The WXM ground localization SNR was 6 in the X-detector and 4.5 in the Y-detector. The localization can be expressed as a 90% confidence circle that is 7.15 arcminutes in radius and is centered at: WXM Ground: RA = +18h 08m 11s, Dec = -20d 39' 21" (J2000), which was reported in a GCN Notice and flagged as a known X-ray source. Further analysis of the WXM data has produced a refined localization that can be expressed as a 90% confidence circle that is 6.9 arcminutes in radius and is centered at WXM Refined Ground: RA = +18h 08m 11.2s, Dec = -20d 38' 49" (J2000). Both WXM ground localizations are inconsistent with the burst coming from SGR 1806-20, suggesting that the burst came from a new source. The spectrum of the burst can be well-described by a sum of two blackbody spectra with the following parameters: n_H = 6 x 10^22 cm^-2, kT_1 = 4.20 +/- 0.3 keV, and kT_2 = 10.82 +/- 0.8 keV. The spectrum of the burst is thus typical of SGR bursts; it is too hard to be an XRB and too soft to be a GRB. The burst duration t_90 of the event is 0.16 s in the 7-30 keV energy band, and 0.14 s in the 30-400 keV band. The fluences of the burst are 7.1 x 10^-7 erg cm^-2, 5.7 x 10^-7 erg cm^-2, and 4.7 x 10^-7 erg cm^-2 in the 7-30, 25-100, and 30-400 keV energy bands, respectively. We initially waited to report the refined ground location of the burst in the expectation that confirmation of the location of this possible new SGR would come from the IPN. However, the Ulysses data for this event has unfortunately been lost, due to a malfunction of the DSN antennas. We have subjected the WXM localization of the burst to the following tests: (1) We have localized the burst, using only the WXM wires that were illuminated by the burst and selecting a background interval that does not include any peak from the quasi-periodic brightness oscillations of GRS 1915+105, which was in the FOV of the WXM at the time of the burst. We find that the center of the localization error circle changes by < 1 arcminute. (2) We have localized the burst, using the one WXM X-detector wire that was not illuminated by GRS 1915+105, the Y-detector wire for which the relative contamination by GRS 1915+105 was the least, and a 3 s background interval ending 0.6 s before the beginning of the burst. We find exactly the same localization for the burst as before, except that the statistical error is 9 arcminutes instead of 7 arcminutes. We conclude from these results that the localization of the burst is not significantly affected by the presence of GRS 1915+105 in the FOV of the WXM at the time of the burst. (3) We have localized the burst, assuming that it has a very soft (XRB) spectrum. We find that the center of the localization error circle changes by 2.9 arcminutes in the direction directly away from SGR 1806-20. We conclude from this result that assuming a spectrum that is softer than the spectrum of a GRB increases by a small amount the angular offset of the burst from the known location of SGR 1806-20. (4) There is no evidence for saturation of the WXM. However, we have localized the burst, using only photons in the first 80 ms after the trigger, when the photon count rate of the burst in the WXM was low. We find that the radius of the localization error circle increases to 13.6 arcminutes but that the center of the error circle changes by < 2.5 arcminutes. We conclude from this result that the localization of the burst is not significantly affected by saturation effects. (5) We have carefully inspected the aspect solution from the optical cameras, and have concluded that the solution is accurate to better than 1 arcminute. (6) We have also localized GRS 1915+105, which was in the field of view of the WXM at the time of the burst, using two successive peaks in its quasi-periodic brightness oscillations -- one 25 s before and one 25 s after the burst. The resulting localization has an error radius of 10.4 arcminutes and is centered 2 arcminutes from the known location of GRS 1915+105. We conclude from these two results that the aspect of the spacecraft is well known at the time of the burst, and that other X-ray sources in the the FOV of the WXM do not significantly affect the localization of GRS 1915+105, and therefore presumably do not significantly affect the localization of the burst. We have therefore been unable to find any reason to doubt the accuracy of the WXM localization of the burst. If the probability distribution of the localization were a circularly symmetric Gaussian, the 15.5 arcminute angular offset of SGR 1806-20 from the center of the WXM localization circle of the burst would correspond to a chi^2 of 23.2 for 2 DOF. The known location of SGR 1806-20 would then be inconsistent with the localization of the burst at a formal significance level of 9 x 10^-6. However, although the real probability distribution of the localization of the burst is relatively circularly symmetric, it is very non-Gaussian, especially far out in the tail. The true significance therefore cannot be stated with any confidence, but it is clearly very small. This strongly suggests that the burst came from a new source. We have examined existing ASCA, ROSAT, and Chandra observations of this field. There are no ASCA sources in the WXM error circle for the burst. There are several weak ROSAT sources in the error circle for the burst, but it is not clear that any of them are associated with the burst source. The FOV of the most recent Chandra observation of SGR 1806-20 did not include the WXM error circle for the burst. HETE-2 observations of the field are continuing. Other observations of this possible new SGR are encouraged. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2353 SUBJECT: 030813 SGR event (Konus-Wind observation) DATE: 03/08/18 15:53:32 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, E. Mazets, V. Pal'shin, D. Frederiks (all Ioffe PTI), and T. Cline (NASA GSFC) on behalf of the Konus GRB team, report: Konus - Wind also observed this burst (GCN 2351) at 09:52:01.888 It has a duration of 0.1s and fluence 9x10-7 erg cm-2 (15-200 keV). The only evidence that the burst is not from SGR1806-20 is its hardness ratio N(71 - 280 kev)/N(18.7 - 71 kev) = (0.24 +/- 0.03). An average value for SGR1806-20 bursts detected by Konus-Wind during 1996-2003 is (0.12 +/- 0.01) for the same energy intervals. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2354 SUBJECT: IPN detection of continued activity from SGR1806-20 DATE: 03/08/18 23:28:52 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses and Mars Odyssey GRB teams, I. Mitrofanov, S. Charyshnikov, V. Grinkov, A. Kozyrev, M. Litvak, and A. Sanin, on behalf of the HEND-Odyssey GRB team, and W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr, on behalf of the GRS-Odyssey GRB team, report: Ulysses and Mars Odyssey (HEND) observed this unusually long SGR burst. As observed by Ulysses, it had a duration of approximately 1 second, a 25-100 keV fluence of approximately 7.3E-06 erg/cm2, and a peak flux of approximately 1.9E-05 erg/cm2 s over 0.25 seconds. We have triangulated it to a preliminary annulus centered at RA, Decl(2000)=340.644, -22.919 degrees, whose radius is 63.096 +/-0.013 degrees (3 sigma). As the center line of this annulus passes 0.003 degrees from the position of SGR1806-20, we consider it most likely that this event originated from that SGR. If so, the Earth-crossing time was 50231 seconds. However, due to the present configuration of the IPN, Ulysses/Mars, Mars/Earth, and Ulysses/Earth annuli which are consistent with the position of SGR1806-20 will also be consistent with portions of the error circle for the possible new SGR, 1808-20 (GCN 2351). Depending on the exact position of SGR1808-20, however, the converse is not necessarily true. Thus it may be possible to confirm the existence of this new source with the IPN if it bursts again. The situation is illustrated with a map which has been posted at ssl.berkeley.edu/ipn3/030818. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2355 SUBJECT: Clarification of GCN 2354 on SGR1806-20 DATE: 03/08/19 00:03:26 GMT FROM: Kevin Hurley at UCBerkeley/SSL In case it was not clear from the name of the directory where the map is posted, the SGR burst referred to in GCN 2354 occurred on August 18 2003. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2357 SUBJECT: Summary of recent IPN and HETE detections of SGR bursts DATE: 03/08/20 17:48:01 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses, HETE, Mars Odyssey, and KONUS GRB teams, G. Ricker, J-L Atteia, N. Kawai, D. Lamb, S. Woosley, J. Doty, R. Vanderspek, J. Villasenor, G. Crew, G. Monnelly, N. Butler, J.G. Jernigan, A. Levine, F. Martel, E. Morgan, G. Prigozhin, J. Braga, R. Manchanda, G. Pizzichini, Y. Shirasaki, C. Graziani, M. Matsuoka, T. Tamagawa, K. Torii, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi, T. Tavenner, T. Donaghy, M. Boer, J-F Olive, and J-P Dezalay, on behalf of the HETE GRB team, E. Mazets and S. Golenetskii, on behalf of the Konus-Wind GRB team, I. Mitrofanov, S. Charyshnikov, V. Grinkov, A. Kozyrev, M. Litvak, and A. Sanin, on behalf of the HEND-Odyssey GRB team, W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr, on behalf of the GRS-Odyssey GRB team, D. M. Smith, R. P. Lin, J. McTiernan, R. Schwartz, C. Wigger, W. Hajdas, and A. Zehnder, on behalf of the RHESSI GRB team, and A. von Kienlin, G. Lichti, and A. Rau, on behalf of the INTEGRAL SPI-ACS GRB team, report: The IPN and HETE have observed numerous SGR-like bursts between August 10 and 18. The following table summarizes them. In the one case below where the burst was only observed by Ulysses, the true Earth-crossing time is uncertain by about +/- 3000 s. The time given below is under the assumption that the arrival direction was the general region near SGR1806-20. Date, Earth Observed Localized? GCN Circular August Crossing by Number 2003 Time, s. 10 27050 Ulysses, Konus Yes*** 11 57988 Ulysses, HETE (2800) Yes* 12 31339 Ulysses, Konus Yes*** 13 35523 HETE (2802), Konus Yes** 2351 15 40524 HETE (2806), RHESSI Yes*** 16 82760 Ulysses No 18 41499 HETE (2810) Yes*** 18 50231 Ulysses, HEND, INTEGRAL, Konus Yes* 2354, 2355 *Localization indicates that the most likely source is SGR1806-20 **Localization indicates that the most likely source is SGR1808-20 ***Localization cannot be used to distinguish between SGR1806 and SGR1808 /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2372 SUBJECT: INTEGRAL ToO OBSERVATIONS OF SGR1806-20: CALL FOR CORRELATED OBSERVATIONS DATE: 03/08/29 22:10:44 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and D. Hartmann, on behalf of a large collaboration, report: A 240 ksec INTEGRAL target of opportunity observation of SGR1806-20 has been scheduled for 2003 September 03, starting at 22:45 UT. Simultaneous observations at all wavelengths, but particularly in the NIR (bearing in mind that the reddening is AV=29 mag), are encouraged. The best position for this SGR is the one obtained by Chandra (Eikenberry et al., ApJ 563, L133, 2001; Kaplan et al., ApJ 564, 935, 2002): RA(2000)=18 h 08 m 39.32 s, Decl(2000)=-20 o 24 ' 39.5 " Updates to the INTEGRAL schedule will be posted at: http://astro.estec.esa.nl/integral_webapps/index.jsp?future /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2376 SUBJECT: Radio Observations of SGR1806-20 DATE: 03/09/04 15:41:11 GMT FROM: Dale A. Frail at NRAO M. P. Rupen and D. A. Frail (NRAO) report on behalf of a larger collaboration: "Using the VLA at 8.5 GHz we imaged a 60-arcsec region centered on the Chandra position for SGR 1806-20 (Kaplan et al., ApJ 564, 935, 2002). This short 9 min integration was made on 2003 September 3.15 UT, concurrent with a planned 240 ksec INTEGRAL target of opportunity observation (GCN#2372). No radio source was detected at or near this position. The rms noise was 55 microJy/beam, for a beam size of 450 x 240 mas (p.a. 12 degrees). The min/max within the Chandra ±0.3 arcsec error circle were (-121,+153) microJy/beam. No further observations are planned." /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2377 SUBJECT: IBAS detection of bursts from SGR 1806-20 DATE: 03/09/04 16:49:09 GMT FROM: Sandro Mereghetti at IASF/CNR S.Mereghetti (IASF, Milano), D.Gotz (IASF, Milano) for the ISDC IBAS Localization Team and K.Hurley, on behalf of the INTEGRAL SGR TOO collaboration, report During INTEGRAL TOO observations of the region of SGR 1806-20, performed from 2003 September 3 22:45 UT to September 4 02:54 UT, two bursts have been detected and localized by IBAS. The first burst occurred on September 4 at 00:53:43.9 UT at coordinates R.A. = 18 08 43.6 Dec.= -20 23 28 (J2000). The second one occurred at 01:15:56.9 UT at coordinates R.A. = 18 08 34.3 Dec.= -20 26 25. These localizations have an uncertainty of about 3 arcmin. Therefore the bursts can be confidently associated with SGR 1806-20 and not with SGR 1808-20 (GCN 2351). Both bursts were detected with IBIS/ISGRI in the 15-100 keV range and had a duration of about 200 ms. Their fluences in the 25-100 keV range were about 2x10-9 ergs cm-2 and 2x10-8 ergs cm-2. The TOO INTEGRAL observation of this region (GCN 2372) will continue until September 7 at 03:05 UT. Continued ground-based observations of this region are encouraged. This message can be cited. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2408 SUBJECT: A burst from SGR 1806-20 detected with IBAS DATE: 03/10/07 08:19:08 GMT FROM: Diego Gotz at IASF-CNR D.Gotz (IASF, Milano), S. Mereghetti (IASF, Milano) and M. Beck (ISDC) for the ISDC IBAS Localization Team and F. Mirabel (CEA, Saclay) and the INTEGRAL Science Working Team report During INTEGRAL Galactic Center Deep Exposure a burst originating from SGR 1806-20 has been detected and localized with IBAS at 18:51:27.41 on October 6 2003. The burst was detected with IBIS/ISGRI in the 15-100 keV range and has a duration of about 60 ms. The fluence in the 25-100 keV energy band is about 3x10-8 ergs cm-2. This message can be cited. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2414 SUBJECT: IPN detection of continued activity from SGR1806-20 DATE: 03/10/09 00:02:33 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses and Konus GRB teams, and E. Mazets and S. Golenetskii, on behalf of the Konus-Wind GRB team, report: Ulysses and Konus-Wind observed this event at 12424 seconds on October 08. As observed by Ulysses, it had a duration of approximately 0.1 seconds, a 25-100 keV fluence of approximately 1.2E-06 erg/cm2, and a peak flux of approximately 1.8E-05 erg/cm2 s over 0.03125 seconds. It was followed approximately 50 seconds later by a second event with roughly one-third the intensity. We have triangulated it to a preliminary annulus centered at RA, Decl(2000)= 347.828, -18.495 degrees, whose radius is 70.687 +/- 0.010 degrees (3 sigma). The center line of this annulus passes 0.001 degrees from the position of SGR1806-20, and 0.117 degrees from the position of the AXP XTE J1810-197, excluding the latter as a possible source. This burst probably originated from SGR1806-20, but we note that the annulus also intersects the error circle of the possible new SGR1808-20. This localization may be improved. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2415 SUBJECT: SGR 1806-20 bursts with INTEGRAL and IBAS announcement on Soft Gamma-Ray Repeaters DATE: 03/10/09 08:29:46 GMT FROM: Sandro Mereghetti at IASF/CNR S. Mereghetti, D.Gotz (IASF, Milano) and M. Beck (ISDC) for the ISDC IBAS Localization Team, F. Mirabel (CEA, Saclay) and the INTEGRAL Science Working Team report: During INTEGRAL Core Program observations of the Galactic Center region, IBAS has detected several bursts from SGR 1806-20. They are summarized in the following Table. The positions derived by IBAS with typical errors smaller than 3 arcmin confirm that all of them originated from SGR 1806-20 and not from the nearby sources SGR 1808-20 (GCN 2351) or XTE J1810-197 (IAUC 8168, IAUC 8190). The bursts were detected with the IBIS/ISGRI instrument in the 15-100 keV energy range. Date October 2003 25-100 keV Fluence Duration Day UT (erg cm-2) (s) 6 18:51:27.4 3 x 10-8 0.06 GCN 2408 8 03:27:03.9 4 x 10-7 0.2 (*) 8 03:27:56.1 3 x 10-7 0.2 (*) 8 20:22:06.5 4 x 10-8 0.1 (*) IPN observations of this burst have been reported (GCN 2414) In the near future IBAS will start to distribute automatic Alert Packets for SGR bursts detected with high significance. This will allow rapid follow-up observations at other wavelengths. The source coordinates in the Alert Packets will allow IBAS users to distinguish such events from classical GRBs. This message can be cited. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2417 SUBJECT: SGR1806-20 bursts on 031008. Helicon detection and small error box. DATE: 03/10/10 13:39:04 GMT FROM: Dmitry Frederiks at Ioffe Institute R. Aptekar, S. Golenetskii, E. Mazets, V. Pal'shin, and D. Frederiks on behalf of Konus-Wind and Helicon/Coronas-F teams, T. Cline and K. Hurley, on behalf of the Ulysses and Konus GRB team, Helicon-Coronas-F also observed two SGR bursts (GCN 2414, 2415), first at 03:27:04:070 UT (12424.070 s) and second one at 03:27:56:172 UT (12476.172s). Konus-Wind - Helicon-Coronas-F triangulation gives the annulus centered at RA(2000) = 344.822 deg, Dec(2000) = 0.740 deg, and radius of 74.130 +/- 0.292 deg (3 sigma) (the distance between Wind and Coronas-F was only 1 light second). This annulus intersects the Ulysses-Konus annulus (GCN 2414) to form two error boxes, one of which may be eliminated by the Konus ecliptic latitude response. The resulting error box has an approximate area of 40 sq. arcmin. Its coordinates are: RA(2000) DEC(2000) ERROR BOX CENTER: 272.106 -20.647 ERROR BOX CORNER1: 271.897 -21.447 ERROR BOX CORNER2: 272.310 -19.793 ERROR BOX CORNER3: 272.317 -19.850 ERROR BOX CORNER4: 271.905 -21.505 This error box includes the position of SGR 1806-20. The first burst contains a precursor with a duration ~0.100 s and a main pulse which had a duration ~0.110 s (total duration 0.210 s). The second burst had a duration of approximately 0.380 s . The spectrum of the first burst can be well-described by OTTB model dN/dE ~ E^-1 exp(-E/E0) with E0 = 13.4 +/- 0.7 keV. The fluences are: 13-200 keV 25-100 keV 1st burst: 3.15 x 10^-6 erg/cm2 1.3 x 10^-6 erg/cm2 2nd burst: 1.7 x 10^-6 erg/cm2 7.0 x 10^-7 erg/cm2 The peak fluxes are: 1st burst: 4.0 x 10^-5 erg/cm2 s (over 0.008 s) 2nd burst: 1.5 x 10^-5 erg/cm2 s (over 0.064 s) /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2419 SUBJECT: Ongoing Bursting Activity from SGR 1806-20 detected with IBAS DATE: 03/10/15 12:46:32 GMT FROM: Diego Gotz at IASF-CNR D. Gotz, S. Mereghetti (IASF, Milano) and M. Beck (ISDC) for the ISDC IBAS Localization Team, F. Mirabel (CEA, Saclay) and the INTEGRAL Science Working Team report: Several more bursts from SGR 1806-20 have been detected by IBAS during INTEGRAL Core Program Galactic Center Deep Exposure. Their times, preliminary fluences and durations are summarized in the following table. The positions of the bursts are all consistent with SGR 1806-20 within 2 arcmin. The bursts were detected with the IBIS/ISGRI instrument in the 15-100 keV energy range. Date October 2003 25-100 keV Fluence Duration Day UT (erg cm-2) (s) 11 01:26:27.07 1.0 x 10-8 0.1 14 14:31:45.41 2.0 x 10-8 0.1 15 02:35:19.66 2.0 x 10-8 0.1 15 04:55:00.88 2.0 x 10-7 0.18 15 07:37:47.57 3.0 x 10-8 0.1 (*) 15 07:55:52.97 1.5 x 10-8 0.1 15 07:56:21.07 1.0 x 10-8 2 x 0.1 (**) 15 10:19:31.94 4.0 x 10-8 0.13 15 11:00:28.77 4.0 x 10-8 0.15 15 11:17:05.32 2.0 x 10-8 0.2 (*) This burst is preceeded by a small precursor lasting ~0.05 s (**) This burst consists of two distinct peaks, lasting ~0.1 s each, separated by ~0.2 s. The fluence given is for the first one. The second is has a smaller peak flux, but is harder. This message can be cited. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2422 SUBJECT: IBAS alert 1180 refers to a burst from SGR 1806-20 DATE: 03/10/15 20:14:49 GMT FROM: Diego Gotz at IASF-CNR D. Gotz (IASF, Milano) on behalf of the IBAS localization team reports: IBAS alert 1180 does not correspond to a GRB but to a burst from SGR 1806-20, not black listed due to incorrect attitude. Offline analysis shows that this burst is related to the Soft Gamma Repeater. Details on this and other not yet reported bursts will follow. This message is citeable. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2451 SUBJECT: IPN detection of activity from SGR1806-20 DATE: 03/11/18 18:02:21 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses, Konus, and Mars Odyssey GRB teams, E. Mazets and S. Golenetskii, on behalf of the Konus-Wind GRB team, I. Mitrofanov, S. Charyshnikov, V. Grinkov, A. Kozyrev, M. Litvak, and A. Sanin, on behalf of the HEND-Odyssey GRB team, and W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr, on behalf of the GRS/Odyssey GRB team, report: Konus-Wind and Mars Odyssey-HEND observed this GRB at 26660 seconds on 14 November 2003. As observed by Konus, it had a duration of approximately 1.4 seconds, an 18-200 keV fluence of approximately 3.6E+-05 erg/cm2, and a peak flux of approximately 6.3E-05 erg/cm2 s. We have triangulated it to a preliminary annulus centered at RA, Decl (2000) = 344.192, -8.447 degrees, whose radius is 70.299 +/- 0.036 degrees (3 sigma). As the center line of this annulus passes 0.009 degrees from the position of SGR1806-20, and 0.092 degrees from the center of the error circle of SGR1808-20, we conclude that the origin of this burst was most likely SGR1806-20. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2504 SUBJECT: IPN triangulation of an intermediate burst from SGR1806-20 DATE: 04/01/01 21:01:07 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses, Mars Odyssey, and Konus GRB teams, S. Golenetskii, E. Mazets, V. Pal'shin, and D. Frederiks on behalf of the Konus-Wind and Helicon/Coronas-F teams, I. Mitrofanov, S. Charyshnikov, V. Grinkov, A. Kozyrev, M. Litvak, and A. Sanin, on behalf of the HEND-Odyssey GRB team, W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr, on behalf of the GRS-Odyssey GRB team, and D. M. Smith, R. P. Lin, J. McTiernan, R. Schwartz, C. Wigger, W. Hajdas, and A. Zehnder, on behalf of the RHESSI GRB team, report: Konus-Wind, Helicon, Mars Odyssey - HEND, and RHESSI observed this burst at 60913 s on 28 December 2003. As observed by Konus, its duration was 1.1s, its 15-200 keV fluence was 3x10^(-5) erg/cm2, and its peak flux was 8.6x10^(-5) erg/cm2 s. It had a soft spectrum, with kT=20 keV. Using Konus and Odyssey data, we have triangulated it to a preliminary annulus centered at RA, Decl(2000)=186.046, -2.629 degrees, whose radius is 85.436 +/- 0.028 degrees (3 sigma). As the centerline of this annulus passes 0.011 degrees from the position of SGR1806-20, we believe that this event is an intermediate burst from that source. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2541 SUBJECT: INTEGRAL detection of activity from SGR1806-20 DATE: 04/03/09 11:03:32 GMT FROM: Sandro Mereghetti at IASF/CNR S Mereghetti, D.Gotz, M. Beck and J.Borkowski on behalf of the IBAS Localization Team, S.Shaw and K.Pottschmidt on behalf of the INTEGRAL Science Data Centre and F.Mirabel on behalf the INTEGRAL Science Working Team report: The IBAS alert n.1563 corresponds to a short burst (0.2 seconds) with preliminary position within 1 arcminutes from the soft gamma-ray repeater SGR1806-20. Further off-line data analysis is in progress. This message is citeable. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2542 SUBJECT: IBAS results on a burst from SGR1806-20 DATE: 04/03/09 11:50:46 GMT FROM: Sandro Mereghetti at IASF/CNR D. Gotz, S. Mereghetti (IASF, Milano) for the ISDC IBAS Localization Team, F. Mirabel (CEA, Saclay) and the INTEGRAL Science Working Team report: We confirm that the burst of IBAS alert n.1563 (GCN 2541) originated from SGR1806-20. The burst was detected with the IBIS/ISGRI instrument in the 15-100 keV energy range, during the INTEGRAL Core Program Galactic Center Deep Exposure, at 10:24:08.35 UT of March 9. The preliminary estimate of the burst fluence in the 15-100 keV energy range is 2.2 x 10-7 erg cm-2. We remind that IBAS is also distributing real time Alert Packets for bursts from known SGR positions (see ISDC Newsletter n. 14 http://isdc.unige.ch/Newsletter/N/#ibas and GCN 2415). SGR 1806-20 will be in the INTEGRAL field of view for various time intervals in the next few days, thus possibly giving rise to other IBAS alerts. This message can be cited. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2558 SUBJECT: Summary of recent bursts from SGR 1806-20 detected by INTEGRAL DATE: 04/03/31 15:13:38 GMT FROM: Diego Gotz at IASF-CNR D. Gotz, S. Mereghetti (IASF, Milano), M. Beck (ISDC) on behalf of the IBAS Localization Team, N. Mowlavi and S. Shaw on behalf of the INTEGRAL Science Data Centre and the INTEGRAL Science Working Team report: SGR 1806-20 has been moderately active after the burst of March 9 (Gotz et al. GCN 2542). The times of the bursts discovered with IBAS in the IBIS/ISGRI data are the following: Start time (UT) IBAS Alert Number -------------------------------------------------- 2004-03-09T10:24:08.35 1563 (GCN 2541, 2542) 2004-03-16T13:02:06.43 1677 2004-03-20T06:34:35.05 1685 2004-03-20T17:57:01.83 * 2004-03-29T06:15:40.97 * 2004-03-29T11:46:47.50 * 2004-03-30T17:03:05.81 1716,1717 (*) These bursts have been detected with significance below the threshold for automatic delivery of IBAS Alert Packets The burst of March 30 was among the brightest detected by INTEGRAL from this Soft Gamma-Ray Repeater. It consisted of a main peak lasting about 0.11 s, followed by a smaller peak 0.1 s later. The fluence of the main peak was about 3 x 10-7 erg cm-2 (15-100 keV). This message can be cited. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2603 SUBJECT: IPN triangulation of an intense intermediate burst from SGR1806-20 DATE: 04/05/21 20:13:06 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses and Konus GRB teams, E. Mazets and S. Golenetskii, on behalf of the Konus-Wind GRB team, and D. M. Smith, R. P. Lin, J. McTiernan, R. Schwartz, C. Wigger, W. Hajdas, and A. Zehnder, on behalf of the RHESSI GRB team, report: Konus and RHESSI observed this soft-spectrum burst at 72247 s on May 19 2004. Ulysses was off. Its duration was 1.3 s, its fluence was ~2.8 x 10^-5 erg/cm^2, and its peak flux was ~3.3 x 10^-5 erg/cm^2 s. We have triangulated it to an annulus centered at RA, Decl(2000)=250.249, -19.744 degrees, whose radius is 20.792 +/- 2.019 degrees. As the center line of this annulus passes only 0.2 degrees from the position of SGR1806-20, we believe that it is the source of this event. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2604 SUBJECT: Activivty of SGR 1806-20 DATE: 04/05/28 13:46:43 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks on behalf of Konus-Wind and Helicon/Coronas-F teams, T. Cline on behalf of the Konus-Wind team, and A. Rau, A. von Kienlin, G. Lichti on behalf of the INTEGRAL SPI-ACS GRB team report: Recently, Konus-Wind has detected seven SGR-like bursts in the trigger mode: Date Time, Duration, Fluence, Peak Flux, kT**** s UT s (20-200 keV) (20-200 keV) keV ergs/cm2 ergs/cm2 s ----------------------------------------------------------------------- 040427 47089.452 0.176 (3.43 +/- 0.07)E-6 (2.58 +/- 0.22)E-5 19+/-3 040519* 72250.485 1.376 (2.74 +/- 0.02)E-5 (3.19 +/- 0.09)E-5 21+/-2 040522** 31696.702 0.176 (2.16 +/- 0.06)E-6 (2.82 +/- 0.17)E-5 16+/-5 040522 45772.875 0.136 (1.33 +/- 0.04)E-6 (1.59 +/- 0.12)E-5 25+/-6 040523 50502.964 0.552 (4.32 +/- 0.09)E-6 (2.94 +/- 0.14)E-5 16+/-5 040525*** 12976.933 0.592 (8.74 +/- 0.12)E-6 (3.06 +/- 0.11)E-5 23+/-4 040526 29173.030 0.752 (5.88 +/- 0.11)E-6 (1.41 +/- 0.09)E-5 16+/-5 ------------------------------------------------------------------------ * - this burst was localized, the most like source of the burst is SGR 1806-20 (GCN 2603). ** - this burst was also detected by Helicon-Coronas-F in the background mode. Estimated time delay is consistent with SGR 1806-20 position. *** - this burst was also detected by INTEGRAL SPI-ACS. We have triangulated it to an annulus centered at RA(2000) = 259.389 deg, Decl(2000) = -17.958 deg, whose radius is 12.616 +/- 1.770 deg (3 sigma). The center line of this annulus passes 0.4 degrees from the position of SGR 1806-20. **** - the last column contains the values of spectral parameter kT for the OTTB spectral model: dN/dE ~ E^{-1} exp(-E/kT) Additionally, a number of SGR-like bursts (short and soft) were detected by both Konus detectors S1 and S2 in the background mode: Date Time, s UT (hh:mm:ss) --------------------------- 040519 25976 (07:12:56) 040519 86378 (23:59:38) 040520 44823 (12:27:03) 040522 2693 (00:44:53) 040522 30582 (08:29:42) 040522 80762 (22:26:02) 040522 83738 (23:15:38) 040523 18673 (05:11:13) 040523 39091 (10:51:31) 040523 40937 (11:22:17) 040523 65789 (18:16:29) The Konus ecliptic latitude response indicates that the source of the bursts is near ecliptic plane. All these data lead to the supposal that the all these bursts originated from SGR 1806-20, which, hereby, has entered a new phase of activity in the hard X-ray. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2605 SUBJECT: MASTER: HETE Alert 3274 optical observation DATE: 04/05/30 21:21:43 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, A.Krylov, V.Kornilov, G.Borisov, D.Kuvshinov, A.Belinski, I.Chilingarian, M.Kuznetsov, S.Potanin, G.Antipov, E.Gorbovskoy, N.Tyurina Sternberg Astronomical Institute, Alexsandr Krylov Observatory, Moscow After HETE alert 3274 (Probable GRB, known X-ray sources) MASTER robotic telescope (http://observ.pereplet.ru) had automatically imaging the corresponding area of the sky (58 seconds after trigger time). We have 30 unfiltered images of the error box (30s exposition, 6 square degrees field). Under the bad weather condition the limiting magnitude was about 13. There is no OT at SGR1806-20 position. 29 may UT GRB Time Time delay GRB: 22:14:17.08 0 0 NOTICE: 22:14:38 21 21 NOTICE RECEIVED: 22:14:59 47 26 POINTING: 22:15:05 53 6 IMAGING START: 22:15:10 58 5 Reduced FITS images are available at http://observ.pereplet.ru/images/GRB040529/ These are technical results. This message may be cited. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2607 SUBJECT: SGR 1806-20, potential NIR counterpart DATE: 04/06/08 11:56:28 GMT FROM: Sylvio Klose at TLS Tautenburg C. Kouveliotou (NASA/MSFC), S. Klose (Thuringer Landessternwarte Tautenburg), S. Wachter (Spitzer Science Center), P. Woods (USRA, NASA/MSFC), S. Patel (USRA, NASA/MSFC), J. Greiner (MPE Garching), B. Stecklum (Thuringer Landessternwarte Tautenburg), and M. van der Klis (University of Amsterdam) report: Following the recent activiation in X-rays of SGR 1806-20, we triggered a Target of Opportunity Observation of the source at ESO with VLT/ISAAC. Observations were performed in the Ks band on May 28, 6:24 UT - 6:50 UT. Altogether 14 images were taken, 1 min integrated exposure time each. For the final data analysis we used those images with the best seeing (8 of the 14 images). Within the 0.7 arcsec Chandra error circle as reported by Eikenberry et al. (ApJ 563, L133; their figure 3d), we identify an isolated point source with Ks = 19.6 +/- 0.4. This source might match the position of source 'B' in Eikenberry et al., while their source 'A', which is at the edge of the Chandra error circle, is resolved into at least two components. We tentatively identify either object B or the second component of object A as the potential K-band counterpart of SGR 1806-20. However, further observations are needed during quiescence of the SGR to determine whether one of the two sources is variable in order to firmly establish a connection with SGR 1806-20. We are deebly indebted the ESO staff at Paranal, in particular Poshak Gandhi, for performing the observations. This message can be cited. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2608 SUBJECT: MASTER:HETE Alert 3259 (SRG1806-20) optical observation DATE: 04/06/09 15:58:25 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, A.Krylov, V.Kornilov, G.Borisov, D.Kuvshinov, A.Belinski, I.Chilingarian, M.Kuznetsov, S.Potanin, G.Antipov, E.Gorbovskoy, N.Tyurina Sternberg Astronomical Institute, Alexsandr Krylov Observatory, Moscow After HETE alert 3259 (Probable SRG1806-20) MASTER robotic telescope (http://observ.pereplet.ru) had automatically imaging the corresponding area of the sky. We have 10 unfiltered images of the error box (60s exposition, 6 square degrees field) started at 28 May 2004 22:25:22 UT (after 10 minutes GRB time). The limiting magnitude on the first image was about 17.5. The limiting magnitude on sum was about 18.6. There is no OT at SGR1806-20 within the Chandra error circle as reported by (Eikenberry et al. ApJ 563, L133; Kouveliotou et al., GCN Circ 2607). JPG-images are available at http://observ.pereplet.ru/images/SRG1806-20/040528/ This message may be cited. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2609 SUBJECT: SGR 1806-20: no IR variability of the proposed counterparts DATE: 04/06/09 17:33:11 GMT FROM: Stefano Covino at Brera Astronomical Observatory G.L. Israel, R. Mignani, S. Covino, S. Campana, L. Stella, N. Rea, V. Testa, G. Marconi on behalf of a larger team report: We have imaged in J, H and Ks bands with VLT/NACO the field of SGR 1806-20 on March 9th, 10th, 16th and 17th 2004. Observations were activated after the X-ray burst that occurred on March 9th (Mereghetti et al., GCN 2541). We have detected several sources within the Chandra error circle reported in Eikenberry et al. 2001 (ApJ 563, L133) including those reported in GCN 2607 (Kouveliotou et al.). The monitoring of these objects did not show any variability more significant than 2sigma in the Ks band on time scales from hours up to days. The limiting Ks magnitude was about 21.5. Both the lack of IR variability correlated to the X-ray burst activity and the relatively high IR flux for the proposed counterparts (GCN 2607) suggest that these objects are unlikely the IR counterpart to SGR 1806-20. This message can be cited. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2611 SUBJECT: IPN Summary of SGR1806-20 Activity in 2004 DATE: 04/06/16 20:46:11 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses, HETE, Mars Odyssey, and Konus GRB teams, G. Ricker, J-L Atteia, N. Kawai, D. Lamb, S. Woosley, J. Doty, R. Vanderspek, J. Villasenor, G. Crew, N. Butler, J.G. Jernigan, F. Martel, G. Prigozhin, J. Braga, R. Manchanda, G. Pizzichini, Y. Shirasaki, C. Graziani, Y. Yamamoto, M. Suzuki, M. Matsuoka, T. Tamagawa, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi, T. Tavenner, T. Donaghy, C. Barraud, M. Boer, J-F Olive, and J-P Dezalay, on behalf of the HETE GRB team, S. Golenetskii, E. Mazets, V. Pal'shin, and D. Frederiks, on behalf of the Konus-Wind and Helicon/Coronas-F teams, D. M. Smith, R. P. Lin, J. McTiernan, R. Schwartz, C. Wigger, W. Hajdas, and A. Zehnder, on behalf of the RHESSI GRB team, I. Mitrofanov, S. Charyshnikov, V. Grinkov, A. Kozyrev, M. Litvak, and A. Sanin, on behalf of the HEND-Odyssey GRB team, W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr, on behalf of the GRS-Odyssey GRB team, and A. von Kienlin, G. Lichti, and A. Rau, on behalf of the INTEGRAL SPI-ACS GRB team, report: SGR1806-20 continues to be active in the hard X-ray band, with the most recent bursts observed on 2004 June 15. The following is a summary of all events in 2004 to date which are either confirmed (by imaging or by triangulation) or suspected to originate from this source. "Suspected" means that the event is a short and/or soft spectrum burst, but that it has not been localized. Many recent HETE events have been confirmed by Konus in either triggered or waiting mode data, but not all of them can be triangulated. This list, which includes some events previously mentioned in GCN Circulars, is not meant to be complete. The data of all the IPN spacecraft have not been examined exhaustively yet, and in addition, Earth-blocking and experiment duty cycles prevent many bursts from being detected. At this point, we will only issue future GCN's for exceptional bursts from this source, or exceptionally active periods. DATE DOY TIME SOD 1. 19 JAN 04 19 22:32:59 81179 2. 09 MAR 04 69 10:24:08 37448 3. 16 MAR 04 76 13:02:14 46934 4. 20 MAR 04 80 06:34:37 23677 5. 27 APR 04 118 13:04:49 47089 6. 02 MAY 04 123 21:56:14 78974 7. 03 MAY 04 124 02:40:40 9640 8. 03 MAY 04 124 02:51:38 10298 9. 03 MAY 04 124 14:00:26 50426 10. 15 MAY 04 136 15:02:28 54148 11. 19 MAY 04 140 07:12:56 25976 12. 19 MAY 04 140 20:04:47 72287 13. 19 MAY 04 140 23:59:38 86378 14. 20 MAY 04 141 12:27:03 44823 15. 22 MAY 04 143 00:44:53 2693 16. 22 MAY 04 143 08:29:42 30582 17. 22 MAY 04 143 08:48:13 31693 18. 22 MAY 04 143 12:42:53 45773 19. 22 MAY 04 143 21:39:30 77970 20. 22 MAY 04 143 21:41:47 78107 21. 22 MAY 04 143 21:45:55 78355 22. 22 MAY 04 143 21:57:47 79067 23. 22 MAY 04 143 22:04:39 79479 24. 22 MAY 04 143 22:06:57 79617 25. 22 MAY 04 143 22:26:02 80762 26. 22 MAY 04 143 22:57:50 82670 27. 22 MAY 04 143 23:04:34 83074 28. 22 MAY 04 143 23:06:51 83211 29. 22 MAY 04 143 23:07:34 83254 30. 22 MAY 04 143 23:13:03 83583 31. 22 MAY 04 143 23:15:33 83733 32. 22 MAY 04 143 23:17:50 83870 33. 22 MAY 04 143 23:20:55 84055 34. 22 MAY 04 143 23:23:12 84192 35. 22 MAY 04 143 23:35:39 84939 36. 22 MAY 04 143 23:37:56 85076 37. 23 MAY 04 144 00:35:37 2137 38. 23 MAY 04 144 02:19:18 8358 39. 23 MAY 04 144 05:11:13 18673 40. 23 MAY 04 144 05:35:29 20129 41. 23 MAY 04 144 05:40:05 20405 42. 23 MAY 04 144 07:12:19 25939 43. 23 MAY 04 144 09:03:45 32625 44. 23 MAY 04 144 09:17:43 33463 45. 23 MAY 04 144 10:51:31 39091 46. 23 MAY 04 144 11:22:17 40937 47. 23 MAY 04 144 12:02:24 43344 48. 23 MAY 04 144 13:50:11 49811 49. 23 MAY 04 144 14:01:43 50503 50. 23 MAY 04 144 15:10:08 54608 51. 23 MAY 04 144 15:14:35 54875 52. 23 MAY 04 144 15:18:10 55090 53. 23 MAY 04 144 15:22:23 55343 54. 23 MAY 04 144 15:25:27 55527 55. 23 MAY 04 144 15:25:57 55557 56. 23 MAY 04 144 15:26:00 55560 57. 23 MAY 04 144 15:26:39 55599 58. 23 MAY 04 144 15:27:14 55634 59. 23 MAY 04 144 18:13:47 65627 60. 23 MAY 04 144 18:16:25 65785 61. 23 MAY 04 144 20:32:37 73957 62. 24 MAY 04 145 07:10:07 25807 63. 24 MAY 04 145 07:12:00 25920 64. 25 MAY 04 146 03:36:17 12977 65. 25 MAY 04 146 06:11:59 22319 66. 25 MAY 04 146 16:42:07 60127 67. 25 MAY 04 146 18:19:42 65982 68. 25 MAY 04 146 20:35:09 74109 69. 25 MAY 04 146 21:33:41 77621 70. 26 MAY 04 147 03:53:56 14036 71. 26 MAY 04 147 08:06:13 29173 72. 26 MAY 04 147 10:34:51 38091 73. 26 MAY 04 147 12:34:52 45292 74. 26 MAY 04 147 17:13:56 62036 75. 27 MAY 04 148 04:05:14 14714 76. 27 MAY 04 148 05:53:20 21200 77. 27 MAY 04 148 20:32:55 73975 78. 28 MAY 04 149 20:12:48 72768 79. 28 MAY 04 149 20:31:01 73861 80. 28 MAY 04 149 22:13:55 80035 81. 29 MAY 04 150 22:08:58 79738 82. 29 MAY 04 150 22:14:17 80057 83. 31 MAY 04 152 04:30:45 16245 84. 31 MAY 04 152 04:47:53 17273 85. 31 MAY 04 152 05:54:06 21246 86. 31 MAY 04 152 06:05:23 21923 87. 31 MAY 04 152 08:18:52 29932 88. 31 MAY 04 152 09:17:37 33457 89. 31 MAY 04 152 12:17:12 44232 90. 31 MAY 04 152 14:20:00 51600 91. 31 MAY 04 152 20:34:03 74043 92. 01 JUN 04 153 08:10:18 29418 93. 01 JUN 04 153 11:34:12 41652 94. 02 JUN 04 154 09:30:27 34227 95. 02 JUN 04 154 09:31:32 34292 96. 02 JUN 04 154 09:42:02 34922 97. 02 JUN 04 154 13:48:12 49692 98. 02 JUN 04 154 16:00:02 57602 99. 02 JUN 04 154 19:23:36 69816 100. 03 JUN 04 155 12:38:20 45500 101. 04 JUN 04 156 02:15:59 8159 102. 04 JUN 04 156 08:00:46 28846 103. 05 JUN 04 157 12:58:02 46682 104. 05 JUN 04 157 18:46:13 67573 105. 06 JUN 04 158 00:04:19 259 106. 06 JUN 04 158 08:20:50 30050 107. 06 JUN 04 158 11:09:11 40151 108. 06 JUN 04 158 12:43:25 45805 109. 06 JUN 04 158 12:51:42 46302 110. 06 JUN 04 158 13:03:41 47021 111. 06 JUN 04 158 17:01:01 61261 112. 06 JUN 04 158 23:51:50 85910 113. 07 JUN 04 159 02:05:03 7503 114. 07 JUN 04 159 05:08:15 18495 115. 07 JUN 04 159 11:07:02 40022 116. 08 JUN 04 160 00:21:52 1312 117. 08 JUN 04 160 16:28:34 59314 118. 08 JUN 04 160 22:41:32 81692 119. 09 JUN 04 161 06:21:41 22901 120. 09 JUN 04 161 08:31:26 30686 121. 10 JUN 04 162 00:27:40 1660 122. 10 JUN 04 162 05:38:11 20291 123. 10 JUN 04 162 18:26:23 66383 124. 10 JUN 04 162 21:19:45 76785 125. 10 JUN 04 162 21:29:33 77373 126. 11 JUN 04 163 00:49:23 2963 127. 11 JUN 04 163 02:27:38 8858 128. 11 JUN 04 163 03:44:46 13486 129. 11 JUN 04 163 06:52:04 24724 130. 11 JUN 04 163 10:36:34 38194 131. 11 JUN 04 163 16:43:50 60230 132. 11 JUN 04 163 21:43:15 78195 133. 15 JUN 04 167 00:49:00 2940 134. 15 JUN 04 167 12:00:43 43243 135. 15 JUN 04 167 16:53:57 60837 136. 15 JUN 04 167 23:17:04 83824 /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2633 SUBJECT: Ongoing activity of SGR 1806-20 DATE: 04/07/29 17:31:04 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks on behalf of Konus-Wind and Helicon/Coronas-F teams, T. Cline on behalf of the Konus-Wind team, and A. Rau, A. von Kienlin, G. Lichti on behalf of the INTEGRAL SPI-ACS GRB team report: Since last SGR burst 040615, listed in GCN 2611, Konus-Wind has detected seven SGR-like bursts in the trigger mode: Date Time, Duration, Fluence, Peak Flux, kT* s UT s (20-200 keV) (20-200 keV) keV ergs/cm2 ergs/cm2 s ----------------------------------------------------------------------- 040617 48377.157 0.104 (1.16 +/- 0.04)E-6 (2.28 +/- 0.14)E-5 23+/-3 040622 70209.587 0.332 (5.49 +/- 0.09)E-6 (3.59 +/- 0.18)E-5 17+/-1 040623 81361.257 0.440 (2.49 +/- 0.07)E-6 (1.74 +/- 0.13)E-5 17+/-2 040707 17546.478 0.696 (7.65 +/- 0.12)E-6 (1.86 +/- 0.10)E-5 18+/-1 040719 45188.316 0.264 (3.81 +/- 0.07)E-6 (2.44 +/- 0.21)E-5 20+/-2 040723 42259.178 0.192 (7.51 +/- 0.11)E-6 (5.63 +/- 0.19)E-5 20+/-1 040728 544.709 0.328 (4.36 +/- 0.09)E-6 (2.64 +/- 0.13)E-5 15+/-2 ------------------------------------------------------------------------ * - the last column contains the values of spectral parameter kT for the OTTB spectral model: dN/dE ~ E^{-1} exp(-E/kT) The last burst was also detected by INTEGRAL SPI-ACS at 539.761 s UT. We have triangulated it to an annulus centered at RA(2000) = 302.741 deg, Decl(2000) = -19.181 deg, whose radius is 28.900 +/- 0.478 deg (3 sigma). As the center line of this annulus passes 0.14 degrees from the position of SGR 1806-20, we believe that it is the source of this event. The Konus ecliptic latitude response indicates that the source of the remaining bursts is near ecliptic plane, so we suppose, that they are also originated from SGR 1806-20. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2647 SUBJECT: Bursting activity from SGR 1806-20 detected with IBAS DATE: 04/08/17 09:51:38 GMT FROM: Sandro Mereghetti at IASF/CNR S. Mereghetti, D.Gotz (IASF, Milano), N. Mowlavi, S. Shaw (ISDC), and K.Hurley (UCB/SSL) report: Two weak bursts from SGR 1806-20 have been detected with the IBIS/ISGRI instrument at UT 04:56:19.3 and 05:59:51.3 of 2004 Aug 17. Both bursts lasted 0.1 s and had a fluence of about 1.5x10-8 erg cm-2 (15-100 keV). They had significance below the threshold for automatic delivery of IBAS Alert Packets. INTEGRAL will continue to observe SGR 1806-20 until 03:10 UT of Aug 19. If stronger bursts from this source are detected, automatic Alert Packets will be distributed in real time (expected delay of 10-20 s) This message can be cited. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2665 SUBJECT: Increase of SGR 1806-20 activity DATE: 04/08/26 15:19:46 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks on behalf of Konus-Wind and Helicon/Coronas-F teams, T. Cline on behalf of the Konus-Wind team, and A. Rau, A. von Kienlin, G. Lichti on behalf of the INTEGRAL SPI-ACS GRB team report: Recently the increase of bursting activity from SGR 1806-20 was detected by Konus-Wind, INTEGRAL SPI-ACS, and Helicon-Coronas-F. Konus-Wind has detected 7 bursts in the trigger mode and 5 bursts in the background mode. Additional SGR-like burst was detected by Helicon-Coronas-F in the background mode and triggered INTEGRAL SPI-ACS (the burst was missed by Konus-Wind due to data read out). The most recent burst detected on August 25 at 85512.611 s UT is the brightest burst ever observed by Konus-Wind from SGR 1806-20. The following table summarizes the bursts: Date Time*, Duration, Fluence, Peak Flux, Observed by** s UT s (20-200 keV) (20-200 keV) ergs/cm2 ergs/cm2 s ----------------------------------------------------------------------- 040814 45466.575 0.18 1.6E-6 2.1E-5 K(tr) 040819 22636.891 0.80 1.4E-5 2.5E-5 K(tr) 040820 71208.277 0.06 9.4E-7 3.1E-5 K(tr) 040821 35217 <3 1.7E-6 - K(bg), I 040821 61297.013 0.22 2.5E-6 2.0E-5 K(tr), I 040822 9646 <3 5.0E-7 - K(bg) 040823 22462 <3 8.0E-7 - K(bg) 040823 36755 <3 5.0E-7 - K(bg) 040823 40994.643 0.14 1.5E-6 4.5E-5 K(tr) 040823 48073.891 0.70 1.0E-5 4.2E-5 K(tr), I, H(bg) 040823 48363 <2 3.2E-6 - I, H(bg) 040823 58681 <3 6.0E-7 - K(bg) 040825 85512.611 1.10 2.1E-5 7.0E-5 K(tr), I ------------------------------------------------------------------------ * - Konus-Wind (or Helicon) time is given ** - the last column contains the s/c which observed this burst: K - Konus-Wind, I - INTEGRAL SPI-ACS, H - Helicon-Coronas-F. For Konus and Helicon in the brackets the observation mode is given: tr - trigger, bg - background. The Konus-INTEGRAL annuli for 3 bursts are: Date Time, Center Radius s UT RA DEC and its uncertainty (3sigma) deg deg deg ---------------------------------------------------- 040821 61297.013 310.141 -16.864 35.724+/-0.678 040823 48073.891 311.668 -14.712 37.647+/-0.762 040825 85512.611 314.503 -14.941 40.588+/-0.454 Because all these annuli pass through the position of SGR 1806-20, we believe that it is the source of these events. The Konus ecliptic latitude response indicates that the source of the remaining bursts (except the missed one) is near ecliptic plane, so we suppose, that they are also originated from SGR 1806-20. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2693 SUBJECT: Very bright burst detected from SGR 1806-20 DATE: 04/09/04 09:25:41 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and T. Cline on behalf of Konus-Wind team, G. Ricker, J-L Atteia, N. Kawai, D. Lamb, S. Woosley, J. Doty, R. Vanderspek, J. Villasenor, G. Crew, N. Butler, J.G. Jernigan, F. Martel, G. Prigozhin, A. Dullighan, J. Braga, R. Manchanda, G. Pizzichini, Y. Shirasaki, C. Graziani, M. Matsuoka, T. Tamagawa, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi, T. Donaghy, C. Barraud, M. Boer, J-F Olive, and J-P Dezalay, on behalf of the HETE GRB team, and K. Hurley on behalf of the IPN team report: A very bright SGR burst was detected by Konus-Wind on August 28 at 42581.338 s UT. This burst also triggered HETE at 42569.952 s UT (H3514). We have triangulated it to an annulus centered at RA(2000) = 317.135 deg, Decl(2000) = -17.624 deg, whose radius is 42.448 +/- 1.601 deg (3 sigma). As this annulus includes the position of SGR 1806-20 and Konus ecliptic latitude response indicates that the burst source lays near ecliptic plane, we believe that SGR 1806-20 is the source of this event. As observed by Konus-Wind, the burst had a duration of 0.7 s, a fluence ~4.0x10^-5 erg/cm^2, and a peak flux ~1x10^-4 erg/cm^2 s (both in 20-200 keV range). The value of the spectral parameter kT for an OTTB spectral model (dN/dE ~ E^{-1} exp(-E/kT)) was 26 keV. This burst is the brightest one from this SGR detected so far by Konus-Wind. It is stronger, than the burst on 040825 (GCN 2665) by a factor of about 1.7 in fluence and peak flux. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2706 SUBJECT: An intense burst from SGR1806-20 DATE: 04/09/13 11:41:23 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks on behalf of Konus-Wind and Helicon/Coronas-F teams, T. Cline on behalf of the Konus-Wind team, and A. Rau, A. von Kienlin, G. Lichti on behalf of the INTEGRAL SPI-ACS GRB team report: An intense SGR-like burst was detected by Konus-Wind on September 10 at 35441.919 s (09:50:41.919) UT and Helicon-Coronas-F at 35438.674 s (09:50.38.674) UT. We have triangulated it to an annulus centered at RA(2000) = 325.353 deg, Decl(2000) = -13.289 deg, whose radius is 51.241 +/- 0.156 deg (3 sigma). This burst was also observed by Integral SPI-ACS. The Konus-Wind - INTEGRAL triangulation annulus is: RA(2000) = 322.942 deg, Decl(2000) = -8.645 deg, Radius = 50.227 +/- 0.328 degrees (3 sigma). These annuli intersect to form two error boxes, one of which may be eliminated by the Konus ecliptic latitude response. The remaining error box includes the position of SGR 1806-20, so we believe that it is the source of this event. Additionaly, two SGR-like bursts were detected recently by Konus-Wind. The Konus ecliptic latitude response indicates that the source of these bursts is near ecliptic plane, so we suppose, that they are also originated from SGR 1806-20. The following table summarizes the bursts (as observed by Konus-Wind): Date Time*, Duration, Fluence, Peak Flux, s UT s (20-200 keV) (20-200 keV) ergs/cm2 ergs/cm2 s ----------------------------------------------------------------------- 040830 23313.143 0.14 2.4E-6 3.6E-5 040908 45466.575 0.33 8.3E-6 5.0E-5 040910 35441.919 0.58 1.7E-5 4.6E-5 ------------------------------------------------------------------------ /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2760 SUBJECT: SGR 1806-20 still active DATE: 04/10/04 09:46:14 GMT FROM: Diego Gotz at IASF-CNR D. Gotz, S. Mereghetti (IASF-Milano) and F. Mirabel (SAP, Saclay) report: The soft repeater SGR 1806-20 continues to be in an active bursting state. Six bursts have been detected by IBAS during INTEGRAL Galactic Center Core Program observations, performed between September 30 and October 2, 2004. Burst times, approximate durations, and fluences (15-100 keV) are reported below: Time UT Duration (s) Fluence (erg cm-2) 2004-09-30T13:03:42.07 0.3 4.0E-8 2004-10-01T06:03:29.81 0.2 5.0E-8 2004-10-01T18:45:53.28 0.1 4.5E-8 2004-10-01T22:03:13.29 0.1 1.2E-7 2004-10-02T02:47:29.10 0.15 1.5E-7 2004-10-02T10:10:26.96 0.2 4.5E-7 Being the source very active, IBAS Alert messages regarding SGR 1806-20 are still disabled. This message can be cited. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2763 SUBJECT: Very strong outburst from SGR 1806-20 detected with INTEGRAL DATE: 04/10/05 14:49:51 GMT FROM: Sandro Mereghetti at IASF/CNR S. Mereghetti, D. Gotz (IASF-Milano), J.Borkowski (CAMK-Torun), M.Beck (ISDC-Versoix) on behalf of the IBAS Localization Team and F.I.Mirabel (SAp-Saclay) on behalf of the INTEGRAL Science Working Team report: A strong increase in the activity of SGR 1806-20 has been detcted by IBAS starting at 13:57 UT of October 5. The activity consists of an approximately 6 min long, multipeaked outburst, followed by a few shorter bursts. During the peaks of the long outburst the counting rate in the IBIS/ISGRI detector saturates the available telemetry. Analysis is in progress to estimate the event fluence and spectrum. Rapid observations at other wavelengths are encouraged. This message can be cited. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2764 SUBJECT: Bursts from SGR 1806-20: Preliminary INTEGRAL results DATE: 04/10/05 16:17:17 GMT FROM: Sandro Mereghetti at IASF/CNR D. Gotz, S. Mereghetti (IASF-Milano), F.I Mirabel (SAp-Saclay) report: The activity from SGR 1806-20 reported in GCN Circ. 2763 consists of at least two main bursts whose peak flux and detailed temporal structure are uncertain due to satellite telemetry saturation. Both are detected up to at least 200 keV in the IBIS/ISGRI instrument. The first burst starts at 13:56:43 UT and lasts about 20 s. Its spectrum over the 15-200 keV range is well fit by an Optically Thin Thermal Bremsstrahlung model with temperature kT = 45+/-3 keV. A preliminary analysis gives a lower limit on its fluence of about 1.e-5 erg/cm2 (15-100 keV). The second burst starts at 13:59:33 UT and lasts about 40 s. Its OTTB temperature is kT = 57+/-3 keV and the preliminary lower limit on its fluence is 2.e-5 erg/cm2 (15-100 keV). This message can be cited. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2769 SUBJECT: Konus-Wind observation of a series SGR 1806-20 bursts on 041005 DATE: 04/10/06 14:53:29 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks and T. Cline on behalf of the Konus-Wind team, report: A series of more than 24 short soft bursts triggered Konus-Wind at 50209.639 s UT (13:56:49.639) Observation of this event by the INTEGRAL IBIS/ISGRI attributed it to SGR 1806-20 (GCN 2763, 2764). This series resembles the series of soft bursts from SGR 1900+14 detected on 1998 May 30, three months before giant outburst on 1998 August 27. http://www.ioffe.rssi.ru/LEA/SGR/Catalog/Data/1900/980530a.htm (Aptekar et al., ApJSS v. 137, p. 227) The series consists of two very crowded clusters: from -0.512 s to 17 s and from 165 to 200 s since trigger time (numereous weaker bursts are seen between intense bursts). The total fluence of the bursts is approximately 8.6e-5 ergs/cm2 in 20-200 keV range. The most intense burst started at 7 s after trigger time. It had a duration of ~0.25s and peak flux of 5.7e-5 ergs/cm2 s (in the 20-200 keV range). The spectra of the bursts can be fitted by the OTTB spectral model: dN/dE ~ E^{-1} exp(-E/kT). The spectrum of the starting burst has kT = 19+/-1 keV, the spectrum which includes the most intense burst has kT = 21.1+/-0.6 keV. These values of kT are typical for this SGR. The time-integrated spectrum of the second cluster of the events from 170 s to 195 s has kT = 28+/-1 keV that exceeds the typical kT for this SGR. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2823 SUBJECT: Bright bursts from SGR1806-20 DATE: 04/10/19 13:27:31 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks on behalf of Konus-Wind and Helicon/Coronas-F teams, T. Cline on behalf of the Konus-Wind team, and A. Rau, A. von Kienlin, G. Lichti on behalf of the INTEGRAL SPI-ACS GRB team report: Two bright SGR-like events were detected by Konus-Wind on October 16 at 66284.062s UT and October 17 at 23771.551s UT. Both events were also detected by INTEGRAL SPI-ACS, Wind-INTEGRAL triangulation gives the following annuli: The first event: Alpha = 191.74323 Delta =-17.37563 Radius = 75.32431 +/-0.37658 The annulus passes 0.021 deg (0.17 sigma) from SGR 1806-20. The second event: Alpha = 191.85595 Delta =-16.48234 Radius = 75.45488 +/- 0.27746 The annulus passes 0.053 deg (0.57 sigma) from SGR 1806-20. According to the Konus-Wind data the first event on 041016 had a duration of 0.12 sec, fluence 6.4x10-6 erg cm-2, and peak flux 8.5x10-5 erg cm-2 s-1, both in 20-200 keV range. OTTB fit gives parameter kT = 26.5 +/- 1.5 keV The 041017 event had a duration of main pulse of 1.6 sec, fluence 6.5x10-5 erg cm-2, and peak flux 6.7x10-5 erg cm-2 s-1, both in 20-200 keV range. A considerable spectral evolution was observed, OTTB fit gives the following values of kT during event: ------------------------------------ Time after trigger kT sec keV ------------------------------------ 0 - 0.256s 24.1 +/- 0.5 0.256 - 0.768s 20.4 +/- 0.5 0.768 - 1.6s 17.5 +/- 0.7 ------------------------------------ Following the main pulse there were two weaker events (times are given after the trigger), at +11.287 s (fluence ~2x10-7 erg cm-2) and at +157.2s (fluence ~4.5x10-7 erg cm-2). /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2827 SUBJECT: IBAS GRB Alert # 2034 DATE: 04/10/20 20:51:51 GMT FROM: Diego Gotz at IASF-CNR D. Gotz on behalf of the IBAS Localization Team reports: IBAS Alert number 2034 is due to a burst from SGR 1806-20, incorrectly localized due to wrong attitude information. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2831 SUBJECT: Summary of the recent bursts from SGR 1806-20 DATE: 04/11/04 14:12:33 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks on behalf of Konus-Wind and Helicon/Coronas-F teams, T. Cline on behalf of the Konus-Wind team, and A. Rau, A. von Kienlin, G. Lichti on behalf of the INTEGRAL SPI-ACS GRB team report: SGR 1806-20 remains in the active state. Since the last SGR burst 041017, listed in GCN 2823, Konus-Wind and Helicon-Coronas-F have detected seven SGR-like bursts in the trigger mode. Two of them were also detected by INTEGRAL SPI-ACS. The most recent intense SGR burst was detected by Helicon-Coronas-F today (041104) at 04:17:08.929 UT. Konus-Wind data aren't available yet. The following table summarizes the bursts: Date Time, Instr* Duration, Fluence, Peak Flux, kT** s UT s (20-200 keV) (20-200 keV) keV ergs/cm2 ergs/cm2 s ----------------------------------------------------------------------- 041026 76305.409 K 0.54 3.0E-6 2.4E-5 21.4+/-1.2 041027 35196.737 K 0.55 5.0E-6 2.6E-5 18.6+/-1.1 041029 22099.384 K 0.16 2.5e-6 3.4E-5 17.7+/-1.3 041031(a) 57535.834 H 0.056 4.7e-7 1.2e-5 17.8+/-1.6 041031 61900.552 K, I 0.70 1.2e-5 4.4e-5 18.9+/-0.6 041102(b) 26875.713 K 0.19 1.1e-5 9.9e-5 22.6+/-1.2 041104(c) 15428.929 H, I 1.6 1.9e-5 2.0e-5 21.8+/-0.5 ------------------------------------------------------------------------ * - the intrument, which detected the burst: K = Konus-Wind H = Helicon-Coronas-F I = INTEGRAL SPI-ACS ** - the last column contains the values of spectral parameter kT for the OTTB spectral model: dN/dE ~ E^{-1} exp(-E/kT) (a) - this burst was also observed by Konus-Wind in the background mode. Estimated time delay is consistent with SGR 1806-20 position. (b) - this burst was also observed by Helicon-Coronas-F in the background mode. Estimated time delay is consistent with SGR 1806-20 position. (c) - We have triangulated it to Coronas-INTEGRAL annulus centered at RA(2000) = 225.846 deg, Decl(2000) = 44.432 deg, whose radius is 77.4 ± 4.0 deg (3 sigma). The center line of this annulus passes 0.02 degrees from the position of SGR 1806-20. The Konus-Wind ecliptic latitude response indicates that the source of the remaining bursts is near ecliptic plane, so we suppose, that they are also originated from SGR 1806-20. The peak flux of the burst on 041102 was nearly the same as the peak flux of the brighest burst detected by Konus-Wind from SGR 1806-20 on 040828 (GCN 2693). /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2896 SUBJECT: Very high activity of SGR 1806-20 DATE: 04/12/22 16:57:06 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks and T. Cline on behalf of the Konus-Wind team, report: During 21 December more than 30 SGR-like bursts were detected by Konus-Wind and Helicon-Coronas-F with peak fluxes varied from 5e-7 to 8e-5 erg /cm2 s. The time interval between bursts varied from seconds to hours. The triangulation of several these bursts indicated that their origin is SGR 1806-20. This is the second series of bursts from this source. The previous one was detected on 5 October (GCN 2769). Now we have the data till 01:28 UT December 22. The last burst is seen at 00:50:52 s UT in the Helicon background data. Details on triangulation and the full list of bursts with their characteristics will be given later. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2920 SUBJECT: Giant flare from SGR 1806-20 detected by INTEGRAL DATE: 04/12/29 11:19:07 GMT FROM: Sandro Mereghetti at IASF/CNR J.Borkowski (CAMK, Torun), D. Gotz, S. Mereghetti (IASF, Milano), N.Mowlavi, S.Shaw, M.Turler (ISDC, Versoix), report: A large flare most likely coming from the soft repeater SGR 1806-20 has been detected with INTEGRAL on December 27 at 21:30:26 UT. The flare caused a large and rapid increase in the count rate of the SPI ACS which reached a peak flux of 2x10^6 counts/s (compared to a background level of 88,000 counts/s ). The initial spike, lasting about 1.5 s, is followed by a 300 s long tail in which pulsations at 7.57 s are clearly visible. The IBAS ACS system triggered on a fainter event occurring about 140 s before the main flare and possibly due to a precursor from the same source. No positional information is available with the SPI ACS data. The shape of the light curve, similar to that of the 27 August 1998 flare from SGR 1900+14, but with a periodicity of 7.6 s, indicates that SGR 1806-20 is the most likely origin of the observed event. This would be the first giant flare observed from SGR 1806-20. At the time of the flare, INTEGRAL was pointing at 106 degrees from the direction of SGR 1806-20, which was outside the fields of view of the imaging instruments. See also the News section of http://ibas.mi.iasf.cnr.it/ for further details of the ongoing analysis This message can be cited. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2921 SUBJECT: IPN localization of giant flare from SGR1806-20 DATE: 04/12/29 12:30:42 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses and Mars Odyssey GRB teams, I. Mitrofanov, S. Charyshnikov, V. Grinkov, A. Kozyrev, M. Litvak, and A. Sanin, on behalf of the HEND-Odyssey GRB team, and W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr, on behalf of the GRS-Odyssey GRB team, report: The giant flare observed by INTEGRAL (SPI-ACS - GCN 2920) was also detected by Mars Odyssey (GRS). Data from other IPN spacecraft have not been received yet. A very preliminary analysis indicates that the arrival time at Odyssey is indeed consistent with an arrival direction from SGR1806-20. Further analysis is underway and will be reported later. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2922 SUBJECT: The giant outburst from SGR 1806-20 DATE: 04/12/29 13:18:07 GMT FROM: Dmitry Frederiks at Ioffe Institute E. Mazets, S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, and T. Cline on behalf of the Konus-Wind team, report: On December 27, 2004, the Konus-Wind instrument detected a giant flare from SGR 1806-20. The flare was preceded by a high emission of recurrent soft bursts. A series of numerous bursts occurred on October 5. On the analogy of the behaviour of SGR 1900+14 before the giant flare on 1998 August 27, it was possible to expect, that SGR 1806-20 is close to generation of a giant flare (GCN 2769). Another series began on December 21 and lasted until the giant flare. These bursts were strong in their flux, exhibiting a well pronounced spectral variability and in some cases unusual spectral features. A record of the giant outburst was triggered by a recurrent burst, which was the strongest in the series. The giant outburst occurred on 142 s after this trigger. The flare started with a very intense initial pulse, resulting in overloading of the detector. It was followed by a long pulsating tail lasted more than 380 s. A measured period of the pulsations is 7.57 ± 0.07 s, indicating its increasing since 2000, when value of 7.49 s was determined in Chandra observations of X-ray persistent flux (Kaplan et al., 2002, ApJ, 564, 935) . Giant outbursts were observed earlier in SGR 0526-66 on 1979 March 5, in SGR 1627-41 on 1998 June 18, in SGR 1900+14 on 1998 August 27. The event of December 27 completes this list for all of well known SGRs. After the outburst, SGR 1806-20 continues to emit recurrent bursts. A determination of energetic and spectral parameters of the outburst will take some time because of a huge intensity of the initial pulse. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2923 SUBJECT: Detection of the SGR 1806-20 giant outburst back-scattered by the DATE: 04/12/29 19:32:36 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks on behalf of Konus-Wind and Helicon/Coronas-F teams, and T. Cline on behalf of the Konus-Wind team report: We present an evidence of Helicon-Coronas-F detection of the giant outburst from SGR1806-20 which was scattered back from the Moon. At the time of the outburst SGR1806-20 was occulted by the Earth for Coronas-F. A short burst triggered Helicon at 21:30:29.303s UT on Dec 27. A time delay between Konus-Wind and Helicon-Coronas-F detections is -7.70 s. This value corresponds exactly to burst travelling time from the Wind to the Moon and back to the Coronas-F. The spectrum of the event detected by the Helicon is highly unusual. It looks like a broad assymetric line peaked at ~100 keV. Apparently such a shape corresponds to back-scattering peak of a huge initial pulse of the outburst. The fluence of event is about 7.5x10^-7 erg cm-2 in 25-400 keV range. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2925 SUBJECT: SGR1806-20: Swift-BAT observation of the 041227 super-flare DATE: 04/12/30 19:31:47 GMT FROM: David Palmer at LANL D. Palmer (LANL), S. Barthelmy, L. Barbier (GSFC), S. Campana (OAB), J. Cummings (GSFC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (GSFC/UMD), K. Hurley (UCB), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), K. McLean (LANL), T. Sakamoto (GSFC), G. Sato (ISAS), M. Suzuki (Saitama), M. Tashiro (Saitama), J. Tueller (GSFC) on behalf of the Swift-BAT team: The Burst Alert Telescope (BAT) on Swift triggered on and recorded the super-flare outburst of SGR1806-20 at 21:30:26 2004-12-27. We did not localize the burst because it was outside the coded aperture FOV of the instrument. The angle from the bore sight was 105 degrees, illuminating the instrument from slightly underneath the plane of the detectors through the XRT and UVOT instruments and the body of the spacecraft. Even with the absorption from this material, the main peak countrate in the detector array is saturated at 2.5E6 evts/sec (the maximum count rate the detector electronics is capable of). The FWHM of the main peak was ~0.5 sec. After the main peak, BAT recorded a series of 51 pulsations with a period of 7.56 sec and with three peaks within each pulsation. Prior to the super-flare peak, there was a precursor peak at T-143 sec, The peak count rate (well below the BAT instrumental saturation level) was 31,000 evts/sec (15-350 keV, with nearly all counts below 100 keV) and with a square profile of rise and fall times less than 100 msec and width of 1.2 sec. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2927 SUBJECT: SGR1806-20: RXTE-PCA observation of the 041227 super-flare DATE: 05/01/02 20:10:02 GMT FROM: Craig Markwardt at NASA/GSFC/UMD E. Smith (GSFC/L3), J. Swank(GSFC), C. Markwardt(GSFC/UMD), Y. Rephaeli(UCSD/TAU), D. Gruber(Eureka), M. Persic(Obs.Ast.Trieste), and R. Rothschild (UCSD) The Proportional Counter Array (PCA) on the Rossi X-Ray Timing Explorer (RXTE) detected the precursor and the main flares of SGR 1806-20 on 2004-12-27 (Borkowski et al., GCN #2920). The times of the flares were 21:28:03.5 and 21:30:26.6 UTC, respectively, which agree with the arrival times reported by the Swift-BAT Team (Palmer et al., GCN #2925). Two of the All Sky Monitor detectors were turned off by the high rates. HEXTE detected only the initial 1 s spike of the main flare. The SGR was 31 degrees off the boresight of the 1.1 degree shielded copper collimators of the PCA and the lead collimators of HEXTE. As seen by the PCA, the precursor lasted approximately 1.2 s. After an initial pulse of the main flare, the flux was pulsed at a period of 7.579 +/- 0.002 s (non-barycentered). The PCA observed 3 peaks in the pulses, as did the BAT, during an interval of approximately 360 s. Three PCA detectors were on and recorded peak count rates of 17-25 kct/s (0.125 s bins). However, the detectors were probably saturated during the initial peak of the main flare. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2928 SUBJECT: VLA observations of SGR 1806-20 DATE: 05/01/03 20:27:48 GMT FROM: Patrick B. Cameron at Caltech P. B. Cameron (Caltech) and S. R. Kulkarni (Caltech) report: "We observed the position of SGR 1806-20 with the Very Large Array (VLA) in A-configuration on 2005 Jan 3.81 UT (t ~ 6.9 days after the giant flare, GCN #2920). We detect a radio source coincident with the X-ray position reported by Kaplan et al. (2002, ApJ, 564, 935) at the approximate freqeucnies and flux densities listed below. Freq (GHz) Flux density (mJy) -------------------------------- 4.86 73 8.46 41 This is a factor of brighter of 100 times brighter at 8.46 GHz than SGR 1900+14 at peak. Further observations are planned. The National Radio Astronomy Observatory is operated by Associated Universities, Inc., under cooperative agreement with the National Science Foundation." /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2929 SUBJECT: SGR1806 VLA Observations DATE: 05/01/03 20:43:51 GMT FROM: Chryssa Kouveliotou at MSFC RADIO DETECTION OF SGR 1806-20 FOLLOWING A GIANT FLARE B. M. Gaensler (CfA), C. Kouveliotou (NASA/MSFC, NSSTC), R. Wijers (University of Amsterdam), M. Garrett (JIVE), M. Finger, P. Woods, S. Patel (USRA, NSSTC), M. McLaughlin (Jodrell Bank) report on behalf of a larger team: We observed the soft gamma-ray repeater SGR 1806-20 with the Very Large Array, approximately 7 days after the detection of a Giant Flare from the source (Borkowski, J. et al., 2004, GCN # 2920), on January 3, 2005 for one hour (19:46-20:46 UT). At frequencies of 1.4, 4.9 and 8.5 GHz, we detect an unresolved radio source at coordinates (J2000) RA 18h08m39.3s, Dec -20o24'39.7", with an approximate uncertainty of 0.1" in each coordinate. This is consistent with the X-ray position of SGR 1806-20 as given by Kaplan et al., ApJ 564, 935 (2002). Since this is the first time the source has been observed in radio, we suggest that we detected transient emission from a synchrotron wind bubble, as was seen by Frail et al., Nature, 398, 127 (1999) one to two weeks after a Giant Flare from SGR 1900+14. The preliminary flux density of the source is 160 +/-10, 78 +/-3 and 45 +/-3, mJy at 1.4, 4.9 and 8.5 GHz, respectively. Further observations are planned with the VLA on January 4, 14:15-15:15 UT. We are grateful to the VLA Scheduling Officers (Jim Ulvestadt and Joan Wrobel) for approving our request for Target of Opportunity observations of the source. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2930 SUBJECT: VLA observations of SGR 1806-20 DATE: 05/01/03 21:00:02 GMT FROM: Patrick B. Cameron at Caltech P. B. Cameron (Caltech) and S. R. Kulkarni (Caltech) report: "We observed the position of SGR 1806-20 with the Very Large Array (VLA) in A-configuration on 2005 Jan 3.81 UT (t ~ 6.9 days after the giant flare, GCN #2920). We detect a radio source coincident with the X-ray position reported by Kaplan et al. (2002, ApJ, 564, 935) at the approximate freqeucnies and flux densities listed below. Freq (GHz) Flux density (mJy) -------------------------------- 1.43 164 Further observations are planned. The National Radio Astronomy Observatory is operated by Associated Universities, Inc., under cooperative agreement with the National Science Foundation." /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2931 SUBJECT: DETECTION OF POLARIZATION OF THE RADIO EMISSION FROM SGR 1806-20 DATE: 05/01/03 21:16:21 GMT FROM: Peter Woods at UAH/MSFC DETECTION OF POLARIZATION OF THE RADIO EMISSION FROM SGR 1806-20 B. M. Gaensler (CfA), C. Kouveliotou (NASA/MSFC, NSSTC), R. Wijers (University of Amsterdam), M. Garrett (JIVE), M. Finger, P. Woods, S. Patel (USRA, NSSTC), M. McLaughlin (Jodrell Bank) report on behalf of a larger team: Further to the reports on the radio emission from SGR 1806-20 (Cameron & Kulkarni, GCN 2928, and Gaensler et al, GCN 2929, Atel # 373) we detect linear polarization from the source at 1.4, 4.9, 8.5 GHz at a level of at least 2.6, 0.9, 3.8%, respectively. We caution, however, that these are very preliminary results and more detailed analysis is underway to account for the possibility of polarization leakage from the total intensity signal. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2932 SUBJECT: SGR1806: Detection of a Sudden Ionospheric Disturbance DATE: 05/01/03 23:21:47 GMT FROM: AAVSO GRB Network at AAVSO P. Campbell, M. Hill, R. Howe, J.F. Kielkopf, N. Lewis, J. Mandaville, A. McWilliams, W. Moos, D. Samouce, J. Winkler, G.J. Fishman, A. Price, D.L. Welch, P. Schnoor, A. Clerkin, and D. Saum report, on behalf of the AAVSO International High Energy Network and SID Program, on the detection of the Dec. 27 outburst from SGR 1806-20 (GCN #2920; Borkowski, et. al) as a sudden ionospheric disturbance (SID) in the Earth's atmosphere. A disturbance of the Earth's ionosphere was observed coincident with the INTEGRAL detection of a burst from SGR 1806-20. This SID was seen as a change in the signal strength from Very Low Frequency (VLF) radio transmitters being monitored by stations around the globe. (Note: This is not a radio detection of SGR 1806-20; this disturbance was caused by the prompt X-rays from SGR 1806-20 ionizing the upper atmosphere and modifying the radio propagation properties of the Earth's ionosphere.) The monitoring stations that report detections of the SID are: Observer Receiver Location Transmitter and Location Moos Switzerland FTA - St. Assie, France Hill Massachusetts, USA NAA - Cutler, ME, USA Winkler Texas, USA NAA - Cutler, ME, USA Kielkopf Kentucky, USA NAA - Cutler, ME, USA Campbell Alberta, CA NLK - Jim Creek, WA, USA Howe Colorado, USA NML - LaMoure, ND, USA Mc. Williams Minnesota, USA NML - LaMoure, ND, USA Samouce Montana, USA NML - LaMoure, ND, USA Kielkopf Kentucky, USA NPM - Lualualei, HI, USA (2nd receiver) Mandaville Arizona, USA NPM - Lualualei, HI, USA Lewis California, USA NPM - Lualualei, HI, USA Winkler Texas, USA NPM - Lualualei, HI, USA (2nd receiver) The observing method employs the monitoring of distant, powerful VLF radio transmitters; this is a sensitive monitor of the state of the lower ionosphere along the radio propagation path. Due to the sub-burst longitude and latitude and the geographical distribution of LF/VLF beacons and monitoring stations, this burst was not detected by active monitoring stations in Germany, Australia and Canada. However, one monitoring station in Massachusetts, USA (separate from Hill) did not detect the SID while being in a good location to do so. Several plots of the SID detection are available at: http://www.aavso.org/observing/programs/solar/sid-sgr1806.shtml Additional details of the observations are also available at this site, including the raw data of these and future observations as they become available. Previously, at least four other transient, high-energy sources have produced detectable ionospheric disturbances, as measured with VLF receivers: GRB030329 (Price et. al, IBVS #5415, 2003); GRB830801 (Fishman and Inan, Nature v.331, p.418, 1988); XRF 020427 (GCN 1394), and the Aug. 27, 1998 super-flare from SGR 1900+14 (Inan, et al., Geophys. Res. Lett., v.26, p.3357, 1999). The AAVSO is greatful for generous grants from the Curry Foundation and NASA for the financial support for the High Energy Workshops for Amateur Astronomers. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2933 SUBJECT: Second-epoch VLA observations of SGR 1806-20 DATE: 05/01/04 15:15:00 GMT FROM: Chryssa Kouveliotou at MSFC B. M. Gaensler (CfA), C. Kouveliotou (NASA/MSFC, NSSTC), R. Wijers (U. Amsterdam), M. Garrett (JIVE), M. Finger, P. Woods, S. Patel (USRA, NSSTC), M. McLaughlin (Jodrell Bank), R. Fender (U. Southampton), T. Delaney (CfA) report on behalf of a larger team: We observed the soft gamma-ray repeater SGR 1806-20 with the Very Large Array (VLA) in the A-configuration for a second time on January 4, 2005 for one hour (14:15-15:15 UT). We detect the source at the same coordinates as reported by Gaensler et al. (GCN 2929). Preliminary flux levels, including improved estimates of the fluxes reported in GCN 2929, are as follows (the numbers in parentheses indicate 3 sigma errors in the last decimal points): Frequency Flux (2005 Jan 03.8) Flux (2005 Jan 04.6) (GHz) (mJy) (mJy) --------- -------------------- -------------------- 1.4 172(4) 135(10) 4.9 80(1) 66(2) 8.5 53(1) 38(5) These results indicate a decay in the flux at a rate of approximately 1.9 mJy/hour at 1.4 GHz. At the same time the spectrum has remained constant. On Jan 3, 2005 the spectral index (in the sense F_nu ~ nu^alpha) was alpha = -0.65+/-0.05, while on Jan 4, 2005 the spectral index was -0.61+/-0.06. A reanalysis of the VLA data from 3 Jan 2004 (GCN 2928, 2929) suggests that the radio source associated with SGR 1806-20 is slightly extended at both 4.9 and 8.5 GHz. Assuming that the underlying geometry is an optically thin, spherical thin shell, both data-sets independently suggest a source of approximate diameter 50-100 milliarcseconds. This implies a projected expansion speed of approx (0.3-0.6)c over the 7 days since the initial Giant SGR flare (assuming a source distance of 15.1 kpc; Eikenberry, S. et al., ApJ 616, 506, 2004). Further radio observations of this source with the Westerbork Synthesis Radio Telescope (WSRT), the MERLIN VLBI network and the Parkes Radio Observatory are currently underway or are being scheduled and will be reported as they are analyzed. We will continue monitoring the source with the VLA until it fades below detection level. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2934 SUBJECT: Second Epoch VLA observations of SGR 1806-20 DATE: 05/01/04 17:32:20 GMT FROM: Patrick B. Cameron at Caltech P. B. Cameron (Caltech) and S. R. Kulkarni (Caltech) report: "We observed a second epoch of the position of SGR 1806-20 with the Very Large Array (VLA) in A-configuration on 2005 Jan 4.59 UT (t ~ 7.7 days after the giant flare, GCN #2920). We again detect a radio source coincident with the X-ray position reported by Kaplan et al. (2002, ApJ, 564, 935) at the approximate freqeuncies and flux densities listed below. Freq (GHz) Flux density (mJy) -------------------------------- 1.43 128 +/- 5 4.86 62 +/- 2 8.46 37 +/- 5 Error Bars are 1 sigma. The combination of these measurements with those reported 2005 Jan 03 (GCN #2928, #2929, 2930, ATEL 373) suggest a decay exponent (F ~ t^beta) of beta = -2.2 at 1.4 GHz. The spectral index (F ~ nu^alpha) has remained constant over the two epochs with alpha = -0.74 and -0.68. The National Radio Astronomy Observatory is operated by Associated Universities, Inc., under cooperative agreement with the National Science Foundation." /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2935 SUBJECT: Third epoch observations of SGR 1806-20 with VLA DATE: 05/01/05 16:16:11 GMT FROM: Chryssa Kouveliotou at MSFC B. M. Gaensler (CfA), C. Kouveliotou (NASA/MSFC, NSSTC), J. Gelfand (CfA), R. Wijers (U. Amsterdam), M. Garrett (JIVE), M. Finger, P. Woods, S. Patel (USRA, NSSTC), M. McLaughlin (Jodrell Bank), R. Fender (U. Southampton), T. Delaney (CfA) report on behalf of a larger team: We observed the soft gamma-ray repeater SGR 1806-20 with the Very Large Array (VLA) in the A-configuration for a third time on January 5, 2005 for one hour (mean epoch approx 1600 UT). (See GCN #2928, #2929, #2933; ATEL #373, #375 for earlier results). Preliminary flux levels for 2005-Jan-05.66 are as follows: 4.9 GHz: 57(2) mJy 8.5 GHz: 31(2) mJy The source continues to fade, but at a slower rate consistent with a power law of index -1.6(2) at 4.9 GHz. Further observations will take place on January 6. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2936 SUBJECT: SGR 1806-20, RHESSI observations of the 041227 giant flare DATE: 05/01/05 18:54:11 GMT FROM: Steven E. Boggs at UCB/SSL S. Boggs (UCB), K. Hurley (UCB), D.M. Smith (UCSC), R.P. Lin (UCB), G. Hurford (UCB), W. Hajdas (PSI), C. Wigger (PSI) RHESSI observed both the precursor and the giant flare from SGR 1806-20 in their entirety, staring at 21:28:03.44 UT and 21:30:26.65 UT 2004-12-27 respectively. The SGR was 5 degrees from RHESSI's pointing axis which was directed toward the Sun. This placed the SGR outside the normal imaging FOV of the instrument. During the main peak of the flare the RHESSI spectroscopy detectors were saturated for ~0.5s after the rise, but observed the decay of the main peak and the 400-s long oscillatory component. While the main RHESSI spectroscopy detectors (9 segmented germanium detectors operating from 3 keV to 15 MeV) were saturated during the peak, the RHESSI particle detector (used for detecting SAA passages) was able to measure the incident flux with 0.125-s time resolution in two energy channels determined by thresholds in the electronics: >65 keV, and >650 keV. These data indicate significant emission above 650 keV for ~0.25 s, during the giant flare, and softening of the giant peak during its evolution. In addition, even though the RHESSI spectroscopy detectors are saturated during the giant peak, we can use the reset rates of the preamplifiers to constrain the rise and fall times of the giant peak to <1 ms and ~65 ms respectively. The particle detector data and the spectroscopy detector reset rates allow us to set conservative lower limits to the total fluence of the primary giant peak: >0.1 erg/cm^2 and >0.3 erg/cm^2 respectively. This fluence is >1-2 orders of magnitude higher than the 1998 flare of SGR 1900+14, which had a fluence of 7e-3 erg/cm^2 (Hurley et al., Nature 397, 41, 1999). Assuming a distance of ~15 kpc for SGR 1806-20 (Corbel & Eikenberry, A&A 419, 191,2004) and isotropic emission, we derive a lower limit on the total hard X-ray/gamma-ray energy released in the giant peak to be >8e45 erg. We note that given BATSE's sensitivity of <1e-8 erg/cm^2, this type of giant flare would have been detectable by BATSE (as a short, hard GRB) out to >80 Mpc. When they came out of saturation during the giant peak, the RHESSI spectroscopy detectors were measuring a peak count rate of ~280,000 cnt/s. After the giant peak, RHESSI recorded a series of 51 pulsations with a period of 7.56 s, similar to the INTEGRAL, KONUS, and Swift-BAT observations (Borkowski et al., GCN 2920; Mazets et al., GCN 2922; Palmer et al., GCN #2925). The pulse profile shows evidence for both spectral variations throughout the pulse, and evolution of the pulse shapes throughout the decay. The average 20-100 keV pulse profile shows 3-4 peaks in its structure. During this decay phase, the average 20-100 keV flux is well modeled by the trapped fireball model of Thompson & Duncan (ApJ 561, 980, 2001), with an evaporation time t_evap=382 s, and index a=0.606, where flux ~ (1-t/t_evap)^(a/1-a). Preliminary lightcurves show indications of significant spectral softening during the 400-s oscillatory decay. RHESSI observed the precursor during 21:28:03.44-21:28:04.49 UT, with a peak count rate in the spectroscopy detectors of ~30,000 cnt/s, and ~25,000 counts total. The profile is square, as reported by Swift-BAT (Palmer et al., GCN #2925), with emission extending up to 150 keV. We see a rise time for the precursor <50 ms, and a fall time <100 ms. Results of this analysis will be posted as they come available at: http://www.ssl.berkeley.edu/ipn3/041227 /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2937 SUBJECT: ATCA observations of SGR 1806-20 DATE: 05/01/05 21:01:30 GMT FROM: Chryssa Kouveliotou at MSFC J. Gelfand (CfA), B. M. Gaensler (CfA), K. Newton-McGee (U. Sydney), C. Kouveliotou (NASA/MSFC, NSSTC), R. Wijers (U. Amsterdam), M. Garrett (JIVE), M. Finger, P. Woods, S. Patel (USRA, NSSTC), M. McLaughlin (Jodrell Bank), R. Fender (U. Southampton), T. Delaney (CfA) report on behalf of a larger team: We observed the soft gamma-ray repeater SGR 1806-20 with the Australian Telescope Compact Array (ATCA) on January 5, 2005 for two hours (mean epoch approx 2000 UT). (See GCN #2928, #2929, #2933; ATEL #373, #375 for earlier results). Preliminary flux levels for 2005-Jan-05.83 are as follows: 2.4 GHz: 87(2) mJy 4.8 GHz: 53(1) mJy 8.6 GHz: 29(1) mJy We observe a possible break in the source spectrum. The power law spectral index between 4.8 and 8.6 GHz is -1.0, while between 2.4 and 4.8 GHz the index is -0.7. Further observations will take place on January 6. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2938 SUBJECT: SGR 1806-20: Temporal and Spectral behavior of radio transient DATE: 05/01/06 14:01:30 GMT FROM: Dale A. Frail at NRAO P. B. Cameron (Caltech) and S. R. Kulkarni (Caltech) report: "We have carried out a more thorough calibration of the three VLA epochs of the fading radio source toward SGR 1806-20 (GCN#s 2928, 2929, 2930, 2933, 2934, 2935). Combining this with the data from a fourth epoch observation made with the Australia Compact Array (GCN# 2937) we do a joint fit of the form: F_nu \propto t^\alpha nu^\beta. The best fit values are alpha= -1.62+/-0.06 and beta=-0.75+/-0.03. There is evidence of deviations from this simple power-law behavior. Fitting the decay rate alpha at each frequency we find a systematic steepening. The value of alpha is -1.0 at 1.4 GHz, -1.5 at 4.9 GHz, and -2.2 at 8.5 GHz. This behavior is reminiscent of the broadband afterglow of GRB 991216 (Frail et al. ApJ, 538, 129). A plot of the light curves is at: http://www.aoc.nrao.edu/~dfrail/sgr1806lc.eps. The National Radio Astronomy Observatory is operated by Associated Universities, Inc., under cooperative agreement with the National Science Foundation. The Australia Telescope is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO." /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2939 SUBJECT: SGR 1806-20: Low frequency GMRT results; submission to GCN circulars DATE: 05/01/06 15:16:20 GMT FROM: Poonam Chandra at Tata Inst. Fund.Res. SGR 1806-20: Low frequency GMRT results P. Chandra (Tata Institute of Fundamental Research (TIFR), Mumbai), reports the detection of radio emission from the soft gamma-ray repeater SGR 1806-20 with the Giant Metrewave Radio Telescope (GMRT) in the 610/235 MHz bands for 1.16 hours on 2005 Jan. 04 (mean epoch approximately 0949 UT). The preliminary flux densites for 2005-Jan-04.409 were: 608 MHz: 198.9 (11.9) mJy 240 MHz: 242.6 (14.9) mJy The last digits in the brackets indicate 1 sigma error bars. She notes that the power law index beween the two frequencies is: -0.21 (0.09). This index is substantially flatter than the corresponding power law index reported in the higher frequency VLA observation on 2005 Jan 4.59 UT by Cameron and Kulkarni (GCN 2934) (alpha = -0.74 at 1.4 GHz) or -0.61 (0.06) reported by Gaensler et al at the same time (GCN 2933). Further observations with the GMRT at other low frequencies are also planned. [GCN OPS NOTE (06Jan05): This Circular was delayed by 3 hours until the submitor could be added to the list.] /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2940 SUBJECT: Fourth Epoch VLA observations of SGR 1806-20 DATE: 05/01/06 21:28:18 GMT FROM: Patrick B. Cameron at Caltech P. B. Cameron (Caltech) and S. R. Kulkarni (Caltech) report: "We observed a fourth epoch of the position of SGR 1806-20 with the Very Large Array (VLA) in A-configuration on 2005 Jan 6.77 UT (t ~ 9.9 days after the giant flare. See GCN #2920, #2928, #2929, #2933, #2934, #2935, ATEL #373, #375). We find the following preliminary flux densities: Freq (GHz) Flux density (mJy) -------------------------------- 1.43 96 +/- 2 4.86 39 +/- 2 8.46 24 +/- 1 Error Bars are 1 sigma. We find an angular size at 8.46 GHz of about 80 mas. We see no variation in this diameter over the last 4 days. The National Radio Astronomy Observatory is operated by Associated Universities, Inc., under cooperative agreement with the National Science Foundation." /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2941 SUBJECT: Further ATCA observations of SGR 1806-20 DATE: 05/01/07 15:19:09 GMT FROM: Bryan Gaensler at Harvard-Smithsonian/CfA J. Gelfand (CfA), B. M. Gaensler (CfA), K. Newton-McGee (U. Sydney), C. Kouveliotou (NASA/MSFC, NSSTC), G, Taylor (NRAO), R. Wijers (U. Amsterdam), M. Garrett (JIVE), M. Finger, P. Woods, S. Patel (USRA, NSSTC), M. McLaughlin (Jodrell Bank), R. Fender (U. Southampton) report on behalf of a larger team: We observed the soft gamma-ray repeater SGR 1806-20 with the Australia Telescope Compact Array (ATCA) using five 6-km baselines on January 6, 2005 (0530-0730 UT and 1930-2130 UT) and on January 7, 2005 (0430-0500 UT). Preliminary flux levels, are as follows (the number in parentheses indicates the 1-sigma uncertainty in the last significant figure): Frequency Flux (Jan 06.26) Flux (Jan 06.77) Flux (Jan 07.20) (GHz) (mJy) (mJy) (mJy) --------- ------------ -------------- ----------------- 1.4 103(2) 90(2) 86(3) 2.4 68(2) 66(2) 54(1) 4.8 45(2) 38(1) 6.1 30(2) 8.6 23(1) There is clear evidence for a spectral break from the first two of the above epochs, possibly decreasing to lower frequencies as a function of time. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2942 SUBJECT: SGR 1806-20 and extragalactic short-duration GRBs DATE: 05/01/07 16:31:10 GMT FROM: Arnon Dar at Technion-Israel Inst. of Tech If the giant short peak of the giant flare from SGR 1900+14 on 27/12/2004 (GCN 2920, GCN 2923, GCN 2936, GCN2927) at an estimated distance of 15 kpc (Corbel and Eikenberg A\&A 419, 191, 2004) could have been seen by BATSE as a hard, short-duration GRB up to a distance of 80 Mpc (GCN 2936), then SGRs in external galaxies can be the main source of the hard, short-duration GRBs seen by BATSE: The local optical luminosity within a distance of 80 Mpc is about 10^4 times the Milky Way [MW] luminosity, (\rho_L=1.84 10^8 h L[sun] Mpc^{-3}; L[MW]=2.4 10^{10} L[sun], where, h=0.65, is the Hubble constant in units of 100 km/s/Mpc). If the observed rate from Earth of such bursts per Milky Way luminosity is \sim 1 in 15 years (one since the launch of CGRO), it yields, before correcting for triggering efficiency and for sky solid angle coverage, an observable rate by BATSE of about 2 hard, short-duration, cosmic GRBs per day, independent of the beaming angle. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2943 SUBJECT: Further VLA observations of SGR 1806-20 DATE: 05/01/07 22:09:14 GMT FROM: Bryan Gaensler at Harvard-Smithsonian/CfA B. M. Gaensler (CfA), G. Taylor (NRAO), J. Gelfand (CfA), C. Kouveliotou NASA/MSFC, NSSTC), R. Wijers (U. Amsterdam), M. Garrett (JIVE), G. Taylor (NRAO), M. McLaughlin (Jodrell Bank), R. Fender (U. Southampton), K. Newton-McGee (U. Sydney) report on behalf of a larger team: We observed the soft gamma-ray repeater SGR 1806-20 with the Very Large Array (VLA) in its A configuration on 2005, January 7, UT 2100-2200. Preliminary flux levels at epoch Jan 07.90 are as follows (the numbers in parentheses indicate 1 sigma errors in the last significant figure): Frequency Flux (Jan 07.90) (GHz) (mJy) --------- ------------ 1.4 75(5) 4.8 28(1) 8.6 17(1) The spectrum is consistent with a single power law over this range of spectral index -0.81+/-0.05, significantly steeper than when the radio source was first detected on 2005 Jan 3 (GCN #2928, #2929, $2930). /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2944 SUBJECT: SGR1806: Optical Transient Candidates in SOHO/LASCO Images DATE: 05/01/08 02:54:09 GMT FROM: AAVSO GRB Network at AAVSO P. Schnoor and A. Price, on behalf of the AAVSO International High Energy Network, report on the detection of two transients close to the location of the recent superflare of SGR1806-20 (GCN #2920; Borkowski, et. al) in archival images of the SOHO spacecraft. The C3 telescope, a part of the Large Angle and Spectrometric Coronagraph (LASCO) instrument aboard the SOHO spacecraft, imaged the field of view of the SGR1806-20 superflare before and after detection of the flare on December 27, 2004 at 21:30:26 UT. Two transient objects have been detected in the region near the SGR. The first transient ("A") is nearly coincident with the radio afterglow position reported in GCN #2929 (Gaensler, et al.) of 18h08m39.3s, Dec -20o24'39.7" +/- 0.1" but is only discernable in a single image. The second transient ("B") is discernable in two images (thus is not a cosmic ray) and exhibits variability between the images but its location is further away from the radio afterglow position. Transient A Location: RA 18h08m Dec. -20o26' +/- 2 arc minutes in both directions Date Time (UT) Visual Estimate (v mag) 2004/12/27 23:18 No object down to <9.5 2004/12/27 23:42 6.2 2004/12/28 00:18 No object down to <9.5 Transient B Location: RA 18h06m Dec. -20o31' +/- 2 arc minutes in both directions Date Time (UT) Visual Estimate (v mag) 2004/12/27 22:18 No object down to <9.5 2004/12/27 23:18 7.5 2004/12/27 23:42 6.1 2004/12/28 00:18 No object down to <9.5 The image from 12/27 at 22:42 is not available via the online archive. Astrometry is by visual estimate. The images were taken with no filter and no polarizer. The quantum efficiency of the CCD is about 0.3-0.5 from 500 to 700 nm. Brightness estimates for transient A were made by visual comparison to GSC 6276-1797 (Tycho Vt=6.6) and GSC 6272-0089 (Tycho Vt=6.0). Brightness estimates for transient B were made by visual comparison with GSC 6276-1797 and GSC 6263-0713 (Tycho-2 Vt=8.0). We estimate visual precision to +/- 0.3 mag. Limiting magnitude for all images is estimated with GSC 6276-0854 (Tycho Vt=9.5). This area of the C3 telescope is subject to "strong vignetting" as reported in the LASCO Handbook (1) so astrometry and photometry must be judged as suspect. The authors of this GCN are not trained in analysis of LASCO images so careful calibration by LASCO experts is needed for confirmation. A GCN may be issued in the future when such analysis becomes available. A web page with images, finder chart and an animated, annotated GIF of the LASCO frames is here: http://www.aavso.org/observing/programs/lascosgr.shtml Courtesy of SOHO/LASCO consortium. SOHO is a project of international cooperation between ESA and NASA. 1) http://lasco-www.nrl.navy.mil/handbook/hndbk_6.html /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2945 SUBJECT: SGR1806-20: Swift-BAT observations of two additional bursts DATE: 05/01/09 18:11:58 GMT FROM: David Palmer at LANL D. Palmer (LANL), S. Barthelmy, L. Barbier, J. Cummings (GSFC), E. Fenimore (LANL), R. Fink (GSFC), N. Gehrels (GSFC), D. Hullinger (GSFC/UMD), S. Hunsberger (PSU), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), P. Matteo (ASDC) K. McLean (LANL), J. Nousek (PSU), P. Meszaros (PSU), A. Parsons (GSFC), T. Sakamoto (GSFC), G. Sato (ISAS), M. Suzuki (Saitama), J. Tueller (GSFC) on behalf of the Swift-BAT team: During a follow-up observation on the SGR1806-20, the Burst Alert Telescope (BAT) on Swift has detected two more outbursts, indicating that this source is still in an active phase 11 days after the 041227 giant flare. Each burst was ~0.1 second long and was within BAT's partially-coded (35%) field of view (fully-coded viewing was prevented by the Sun observing constraint). At 2005-01-07 02:08:21 a small outburst (0.4 counts/cm^2, 15-100 keV) was localized on-board at RA=272.154, DEC=-20.374 (J2000) (6 arcmin from the VLA position, Gaensler et al., 2005 GCN#2920). At 2005-01-07 13:12:27 a larger but softer outburst (1.6 counts/cm^2, 15-100 keV) was localized on-board at RA=272.156, DEC=-20.409 (J2000) (0.5 arcmin from the VLA position). /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2946 SUBJECT: SGR 1806-20: Further VLA Observations DATE: 05/01/10 15:10:43 GMT FROM: Patrick B. Cameron at Caltech P. B. Cameron (Caltech) and S. R. Kulkarni (Caltech) report: "We observed the soft gamma-ray repeater SGR 1806-20 with the Very Large Array (VLA) in A-configuration on 2005 Jan 10.60 UT. We find the following preliminary flux densities: Freq (GHz) Flux density (mJy) -------------------------------- 8.46 8 +/- 1 The National Radio Astronomy Observatory is operated by Associated Universities, Inc., under cooperative agreement with the National Science Foundation." -------------------------------------- P. Brian Cameron Caltech Astrophysics Phone: (626) 395-6857 /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2947 SUBJECT: SGR 1806-20: Further low frequency GMRT results DATE: 05/01/13 15:01:53 GMT FROM: Poonam Chandra at Tata Inst. Fund.Res. SGR 1806-20: Further low frequency GMRT results P. Chandra on behalf of GMRT observatory reports the detection of radio emission from the SGR 1806-20 with the Giant Metrewave Radio Telescope (GMRT) in the 610 MHz band (with resolution 6-10") on the following dates: 608 MHz: 6 Jan 2005 111.8 (6.6) mJy 7 Jan 2005 98.8 (29.3) mJy 8 Jan 2005 83.8 (9.2) mJy 9 Jan 2005 74.3 (14.5) mJy The values quoted here are after subtracting the extended emission contribution from the SGR and doing the Tsys corection by a factor of 1.8. The modified value of 608 MHz flux density on 4 Jan 2005 observation is 231.7 (16.7) mJy (uncorrected value 199 mJy in reported in GCN 2939). This new value is after subtracting the extended emission from the SGR and modified with Tsys correction factor of 1.8. We shall report separately the 235 MHz band fluxes of SGR 1806-20 on these days (including 4 Jan 2005 observations (reported in GCN 2939)) treated similarly. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2948 SUBJECT: SGR 1806-20: Further VLA Observations DATE: 05/01/13 20:20:42 GMT FROM: Patrick B. Cameron at Caltech On Mon, 10 Jan 2005, P Brian Cameron wrote: P. B. Cameron (Caltech) and S. R. Kulkarni (Caltech) report: "We observed the soft gamma-ray repeater SGR 1806-20 with the Very Large Array (VLA) in A-configuration on 2005 Jan 13.8 UT. We find the following preliminary flux densities: Freq (GHz) Flux density (mJy) -------------------------------- 8.46 5.3 +/- 0.4 The National Radio Astronomy Observatory is operated by Associated Universities, Inc., under cooperative agreement with the National Science Foundation." /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2950 SUBJECT: SGR 1806-20: RXTE/PCA pulse frequency during flare DATE: 05/01/14 18:00:12 GMT FROM: Peter Woods at UAH/MSFC Pulse Frequency of SGR 1806-20 during the Giant Flare P.M. Woods, M. Finger, S. Patel (USRA, NSSTC), C. Kouveliotou (NASA/MSFC, NSSTC), Y. Rephaeli (UCSD), D. Gruber (Eureka), M. Persic (Obs.Ast.Trieste), R. Rothschild (UCSD), D. Palmer, N. Gehrels, S. Barthelmy, E. Smith, J. Swank, and C. Markwardt (GSFC) report: We have re-analyzed the RXTE PCA data of the giant flare of 2004 December 27 from SGR 1806-20. We find that the pulse period reported in GCN #2927 of 7.579 +/- 0.002 s was strongly biased by pulse profile changes during the tail of this flare. Excluding the first ~60 s of the flare where pulse profile changes are strongest, we measure a barycenter-corrected pulse period of 7.5605 +/- 0.0006 s, significantly different than the previously reported measurement. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2953 SUBJECT: MASTER:GRB050117 SWIFT DATE: 05/01/17 15:33:32 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, A.Krylov, V.Kornilov, G.Borisov, D.Kuvshinov, A.Belinski, M.Kuznetsov, S.Potanin, G.Antipov, E.Gorbovskoy, N.Tyurina Sternberg Astronomical Institute, Alexsandr Krylov Observatory, Moscow After SWIFT alert (GCN 2951) MASTER robotic telescope (http://observ.pereplet.ru) had imaging the corresponding area of the sky. We have unfiltered images of the error box (45s exposition, 6 square degrees field) started at 17 Jan 2005 14:58:40 UT (after 2 hours GRB time). The limiting magnitude on the first image was about 17.0. There is no OT within the SWIFT error circle. JPG-images are available at http://observ.pereplet.ru/images/SRG1806-20/050117/ Observations are continued. This message may be cited. This work is partly supported by RFFI 04-02-16411. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2954 SUBJECT: GRB050117: MASTER optical observations DATE: 05/01/17 17:43:37 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, A.Krylov, V.Kornilov, G.Borisov, D.Kuvshinov, A.Belinski, M.Kuznetsov, S.Potanin, G.Antipov, E.Gorbovskoy, N.Tyurina Sternberg Astronomical Institute, Moscow After SWIFT alert (GCN 2951) MASTER robotic telescope (http://observ.pereplet.ru) had imaging the corresponding area of the sky under the bad weather conditions. We have 50 unfiltered images of the error box (45s exposition, 6 square degrees field) started at 17 Jan 2005 14:58:40 UT (2 hours after GRB time). The limiting magnitude on the summ of the best 10 images was about 19.0. There is no OT within the 0'5 SWIFT error circle. The central part of the JPG-images are available at http://observ.pereplet.ru/images/SRG1806-20/050117/summ10.jpg This message may be cited. This work is partly supported by RFFI 04-02-16411. Mailto: lipunov@sai.msu.ru /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2994 SUBJECT: SGR 1806-20: low frequency GMRT results of 2005 Jan 16. DATE: 05/01/28 18:25:21 GMT FROM: Poonam Chandra at Tata Inst. Fund.Res. SGR 1806-20: low frequency GMRT results of 2005 Jan 16. P. Chandra, D. V. Lal, and C. H. Ishwara-Chandra on behalf of GMRT observatory report the detection of radio emission from the SGR 1806-20 with the Giant Metrewave Radio Telescope (GMRT) observed on 16 Jan 2005 at the following frequencies: 240 MHz (Jan 16.25 UT): 96.1 +/- 22.5 mJy 608 MHz (Jan 16.25 UT): 30.7 +/- 5.0 mJy 1060 MHz (Jan 16.37 UT): 19.9 +/- 1.6 mJy The values quoted here are after subtracting the nearby extended emission contribution from the SGR 1806-20 and modifying the flux densities with a Tsys correction factor of 3.87, 1.93 and 1.59 for 240, 608 and 1067 MHz frequencies respectively. Tsys correction is needed because, within the galactic plane the Tsys is dominated by Tsky, which is proportional to Tsys-towards-SGR and the Tsys-towards-Flux Cal. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2995 SUBJECT: SGR 1806-20: GMRT results at 240 MHz band. DATE: 05/01/28 18:41:28 GMT FROM: Poonam Chandra at Tata Inst. Fund.Res. SGR 1806-20: GMRT results at 240 MHz band. P. Chandra on behalf of GMRT observatory reports the detection of radio emission from the SGR 1806-20 with the Giant Metrewave Radio Telescope (GMRT) in the 235 MHz band (resolution 12"-18") on the following dates: 240 MHz: 2005 Jan 4.41 UT: 465.8 +/- 28.3 mJy 2005 Jan 6.38 UT: 462.3 +/- 29.1 mJy 2005 Jan 7.25 UT: 231.0 +/- 20.2 mJy 2005 Jan 8.24 UT: 249.6 +/- 17.1 mJy 2005 Jan 9.26 UT: 175.5 +/- 19.8 mJy 2005 Jan 10.16 UT: 155.4 +/- 08.5 mJy 2005 Jan 26.26 UT: 103.9 +/- 31.0 mJy The values quoted here are after subtracting the nearby extended emission contribution from the SGR and doing the Tsys corection by a factor of 3.875 at 240 MHz frequency. Tsys correction is required because of the different sky temperatures off the galactic plane (position of SGR) and off the galactic plane (Flux calibrator). The 608 flux density on Jan 10.16 UT and Jan 26.26 UT are 82.4 +/- 6.8 mJy and 19.3 +/- 5.9 mJy, after doing the Tsys correction by a factor of 1.87. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3002 SUBJECT: SGR1806-20: Swift-BAT detection of a large normal burst DATE: 05/01/30 23:52:20 GMT FROM: Scott Barthelmy at NASA/GSFC G. Sato (ISAS), L. Antonelli (INAF-OAR), S. Barthelmy, L. Barbier (GSFC), M. Cropper (MSSL), J. Cummings (GSFC), E. Fenimore (LANL), R. Fink (GSFC), M. Galassi (LANL), N. Gehrels (GSFC), D. Hullinger (GSFC/UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), P. Meszaros (PSU), K. McLean (LANL), D. Palmer (LANL), A. Parsons, T. Sakamoto (GSFC), M. Suzuki (Saitama), J. Tueller (GSFC) on behalf of the Swift-BAT team: Swift-BAT triggered on an outburst from SGR1806-20 at 22:38:26.86 UT 30 Jan 05. This is a large normal burst from this source. The peak rate is 340,000 cnts/sec (1-sec average). There was a single spike with a 0.4-sec rise, a 4.2-sec decay, with additional emission extending out to ~T+15 sec. On top of this tail, there are five spikes at T+7, T+17, T+32, T+85, and T+118sec. The fluence is ~1x10e-5 erg/cm2 (15-350 keV). We note that this is five orders of magnitude smaller than the giant flare from this source on 27 Dec 04. Also note that there was a burst from this source earlier today at 20:45:26 UT with a peak rate of ~4000 cnts/sec (0.128-sec average) and a duration of ~0.5 sec. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3070 SUBJECT: Ongoing activity of SGR 1806-20 after the giant flare DATE: 05/03/05 15:47:16 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks on behalf of Konus-Wind and Helicon/Coronas-F teams, and T. Cline on behalf of the Konus-Wind team report: SGR-like burst 050304 was detected by Konus-Wind at 10:17:14.537 UT and Helicon-Coronas-F at 10:17:17.941 UT. We have triangulated it to an annulus centered at RA(2000) = 321.683 deg, Decl(2000) = -15.478 deg, whose radius is 47.167 ± 0.092 deg (3 sigma). As the center line of this annulus passes 0.033 degrees (1.1 sigma) from the position of SGR 1806-20 and the Konus ecliptic latitude response indicates that the source of the burst is near ecliptic plane, we conclude that this burst originated from SGR 1806-20. The burst had a duration of 0.13 sec, fluence 7.9x10-7 erg cm-2, and peak flux 8.7x10-6 erg cm-2 s-1, both in 20-200 keV range. The time-integrated spectrum of the burst can be fitted by the OTTB spectral model: dN/dE ~ E^{-1} exp(-E/kT), with kT = 22 ± 1 keV. Since the giant flare on 2004 December 27, Konus-Wind and/or Helicon-Coronas-F has detected 10 SGR-like bursts in the trigger mode, probably originated from SGR 1806-20. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3138 SUBJECT: Swift-BAT detection of a bright outburst from SGR1806-20 DATE: 05/03/23 03:31:54 GMT FROM: Scott Barthelmy at NASA/GSFC S. Barthelmy, L. Barbier (GSFC), J. Cummings (GSFC/NRA), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), M. Suzuki (Saitama), J. Tueller (GSFC) on behalf of the Swift-BAT team: At 02:38:21.10 2005-03-23 UT Swift-BAT triggered on a bright outburst from SGR1806-20. There were two short peaks each ~0.4 sec in duration, each with a peak count rate of ~160,000 counts/sec. There was a smaller pre-trigger peak of ~30,000 counts/sec at T-0.7 sec. More than 99% of the emission is below 100 keV. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3343 SUBJECT: Renewal of SGR 1806-20 activity DATE: 05/05/03 15:18:35 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks on behalf of Konus-Wind and Helicon/Coronas-F teams, and T. Cline on behalf of the Konus-Wind team, and A. Rau, A. von Kienlin, G. Lichti on behalf of the INTEGRAL SPI-ACS GRB team report: On May 2 Konus-Wind detected two SGR-like bursts in the trigger mode. The first one triggered Konus-Wind at 5376.421 s UT (01:29:36.421). It was also detected by INTEGRAL SPI-ACS. Because the burst was soft, the SPI-ACS response is very weak, and precise triangulation of this burst is not possible. We conservatively estimated that the time delay was 3.6 +/- 0.4 s which is consistent with the expected time delay for SGR 1806-20 (=3.651 s). Additionaly, the Konus ecliptic latitude response indicates that the burst source is near the ecliptic plane, so we believe that this burst originated from SGR 1806-20. The burst is unusually long with a duration of ~4.5 s, but relatively weak. As observed by Konus-Wind, the burst had a fluence ~2.0x10^-5 erg/cm2, and a peak flux ~6x10^-6 erg/cm2 s (both in 20-200 keV range). The time-integrated spectrum of the burst is well fitted by the OTTB spectral model: dN/dE ~ E^{-1} exp(-E/kT) with kT = 18 +/- 1 keV, which is typical for this SGR. The second burst triggered Konus-Wind at 18502.741 s UT (05:08:22.741). As observed by Konus-Wind, it had a duration ~1 s, a fluence ~4.5x10^-6 erg/cm2, a peak flux ~3.7x10^-6 erg/cm2 s (both in 20-200 keV range). Another two SGR-like bursts (soft and short) were observed by Konus-Wind in the background mode at 5021 s UT (01:23:41) and 16740 s UT (04:39:00) (also on May 2). The last burst was also detected by Helicon-Corronas-F in the background mode. The estimated time delay is consistent with SGR 1806-20 position. The Konus ecliptic latitude response indicates that the source of all these bursts is near the ecliptic plane, so we suppose, that they are also originated from SGR 1806-20. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3385 SUBJECT: GRB 050509b: Swift-BAT refined analysis of the short hard burst DATE: 05/05/09 07:06:49 GMT FROM: Scott Barthelmy at NASA/GSFC S. Barthelmy (GSFC), L. Barbier (GSFC), J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), M. Suzuki (Saitama), J. Tueller (GSFC), T. Mitani (ISAS), F. Marshall (GSFC), T. Takahashi (ISAS) on behalf of the Swift/BAT team: At 04:00:19.23 UT Swift-BAT detected GRB 050509b (trigger=118749) (GCN Circ 3381, C. Hurkett et al.). The refined BAT ground position is (RA,Dec) = 189.073,+28.991 {12:36:18,28:59:28} +- 2.8 arcmin [deg; J2000], (95% containment). This is 59 arcsec from the XRT position (Kennea et al., GNC 3383). The burst was in the fully-coded FOV. Using the event-by-event data, the lightcurve shows a single spike with a duration of ~30msec. Further, the hardness ratio S(50-100)/S(25-50) of ~1.5 puts this burst cleanly in the short-hard cluster on the hardness_ratio vs duration scatter-plot. Using a simple power-law model, the photon index of the time-averaged spectrum is 1.5 +- 0.4. The fluence in the 15-350 keV band is (2.3 +- 0.9) x 10^-8 erg/cm2. The 1-s peak photon flux in the 15-350 band is (1.57 +- 0.36) ph/cm2/s. All the quoted errors are at the 90% confidence level. We note that location is consistant with the galaxy cluster NSC J123610+285901 which has a redshift of z=0.22, which roughly translates to a distance of ~1 Gpc. We also note that at this distance and the observed flux, this is is an order of magnitude farther than the 27-Dec-04 SuperFlare event from SGR1806-20 could be seen. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3545 SUBJECT: Konus-Wind observation of an intermediate burst from SGR 1806-20 DATE: 05/06/13 13:29:10 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks on behalf of Konus-Wind and Helicon/Coronas-F teams, and T. Cline on behalf of the Konus-Wind team report: An SGR-like burst 050611 triggered Konus-Wind at 58099.759 s UT (16:08:19.759). It was detected and localized by HETE WXM (HETE trigger 3800). The HETE error box includes the position of SGR 1806-20, so we conclude that this burst originated from this SGR. The burst had a duration of ~2.3 sec, fluence (8.41 ± 0.12)10-6 erg/cm2, and peak flux on 16-ms time scale (8.6 ± 0.9)10-6 erg/cm2 s (both in 20-200 keV range). The time-integrated spectrum of the burst can be fitted by the OTTB spectral model: dN/dE ~ E^{-1} exp(-E/kT), with kT = 19 ± 1 keV. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3547 SUBJECT: H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE DATE: 05/06/14 16:10:24 GMT FROM: Kevin Hurley at UCBerkeley/SSL H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE K. Hurley, J-L. Atteia, M. Boer, J-F Olive, and J-P Dezalay, on behalf of the HETE FREGATE Team; C. Graziani, M. Arimoto, T. Donaghy, E. Fenimore, M. Galassi, J. Kotoku, M. Maetou, M. Matsuoka, Y. Nakagawa, T. Sakamoto, R. Sato, Y. Shirasaki, M. Suzuki, T. Tamagawa, K. Tanaka, Y. Yamamoto, and A. Yoshida, on behalf of the HETE WXM Team; G. Prigozhin, G. Ricker, N. Kawai, D. Lamb, and S. Woosley, on behalf of the HETE Science Team; N. Butler, G. Crew, J. Doty, R. Vanderspek, J. Villasenor, J. G. Jernigan, A. Levine, G. Azzibrouck, J. Braga, R. Manchanda, and G. Pizzichini, on behalf of the HETE Operations and HETE Optical-SXC Teams; report: The HETE FREGATE, WXM, and SXC instruments detected and localized two bursts from SGR1806-20 on 2005 June 11. H3800 at 16:08:15 (58095 SOD) was an intense, intermediate burst consisting of a single pulse with a rise time < 1 ms and a duration ~2.2 s. The WXM flight localization can be expressed as a circle of radius 14 arcminutes (90% confidence) that is centered at WXM-flight: RA = 18h 08m 07s, Dec = -20d 18' 26" (J2000). The first flight localization was distributed in a GCN Notice issued at 16:23:57 UT. Ground analysis of the SXC data produced an 80" (90%) confidence circle about RA = 18h 08m 39.2s, Dec = -20d 24' 11.2", i.e. consistent with SGR1806-20. A preliminary spectral analysis indicates that this burst may be fit over the 6 - 150 keV energy range by a two blackbody model (Olive et al. Ap. J. 616, 1148, 2004) whose temperatures are kT=4.6 and 10.3 keV. The fluence over this energy range is 1.7E-05 erg cm^-2. This burst was also observed by Konus-Wind (GCN 3545) and RHESSI. H3801 at 19:39:35 (70775 SOD) was a more typical short, weak burst whose duration was <160 ms. This burst was observed by FREGATE, the WXM, and the SXC. Ground analysis of the data produced a localization that can be expressed as a circle of radius 12 arcminutes (90% confidence) that is centered at RA = 18h 08m 34s, Dec = -20d 20m 13s (J2000) These two bursts, in addition to the two short-duration events H3784 (2005 June 02, 11031 SOD) and H3787 (2005 June 06, 39888 SOD) indicate that SGR1806-20 remains active. Further observations at all wavelengths are encouraged. This message may be cited. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3782 SUBJECT: Detection of an intermediate burst from SGR 1806-20 on August 8 DATE: 05/08/10 14:42:12 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks on behalf of Konus-Wind and Helicon/Coronas-F teams, and T. Cline on behalf of the Konus-Wind team report: A SGR-like burst 050808 triggered Konus-Wind at 67438.919 s UT (18:43:58.919). It was also detected by Helicon-Coronas-F in the waiting mode. We have triangulated it to a wide annulus centered at RA(2000) = 302.888 deg, Decl(2000) = -22.871 deg, whose radius is 31.070 ± 3.188 deg (3 sigma). As the center line of this annulus passes 2.46 degrees (2.3 sigma) from the position of SGR 1806-20 and the Konus ecliptic latitude response indicates that the source of the burst is near ecliptic plane, we believe that this burst originated from SGR 1806-20. The burst had a duration of ~1.1 sec, fluence (6.9 ± 0.2)10-6 erg/cm2, and peak flux on 64-ms time scale (1.2 ± 0.3)10-5 erg/cm2 s (both in 20-200 keV range). The burst light curve demonstartes nearly linear decline during ~1 s (the burst rise was missed by Konus-Wind; the total burst duration was estimated combining the K-W background and trigger data). The time-integrated spectrum of the burst can be fitted by the OTTB spectral model: dN/dE ~ E^{-1} exp(-E/kT), with kT = 18.5 ± 0.8 keV. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3784 SUBJECT: Ongoing activity of SGR 1806-20: an intermediate burst 050811 DATE: 05/08/12 11:29:07 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and T. Cline on behalf of the Konus-Wind team, and A. Rau, A. von Kienlin, G. Lichti on behalf of the INTEGRAL SPI-ACS GRB team report: A SGR-like burst 050811 triggered Konus-Wind at 48952.617 s UT (13:35:52.617). It was also detected by Integral SPI-ACS. We have triangulated it to an annulus centered at RA(2000) = 301.581 deg, Decl(2000) = -17.751 deg, whose radius is 28.122 +/- 1.686 deg (3 sigma). As the center line of this annulus passes 0.23 degrees (0.41 sigma) from the position of SGR 1806-20 and the Konus ecliptic latitude response indicates that the source of the burst is near ecliptic plane, we conclude that this burst originated from SGR 1806-20. The burst had a duration of ~2.3 sec, fluence (1.70+/- 0.17)10-5 erg/cm2, and peak flux on 48-ms time scale (1.8 +/- 0.1)10-5 erg/cm2 s (both in 20-200 keV range). The time-integrated spectrum of the burst is well fitted by the OTTB spectral model: dN/dE ~ E^{-1} exp(-E/kT), with kT = 18.2 +/- 0.6 keV. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3927 SUBJECT: GRB 050906: Bright galaxy in BAT error box DATE: 05/09/06 11:42:14 GMT FROM: Andrew Levan at U.of Leicester Andrew Levan, Nial Tanvir (University of Hertfordshire) The BAT error box for the possible GRB 050906 (Swift trigger #=153866, Krimm et al. GCN 3926) contains the bright (K~11), low redshift galaxy IC 328 (part of a small group) at z=0.03 (130 Mpc). Such galaxies are rare in GRB error boxes. If GRB 050906 is a long duration GRB the presence of the galaxy could be indicative of a GRB 980425/SN1998bw -like event. If the burst is short then the distance to IC 328 is somewhat larger than the distance at which the giant flare from SGR 1806-20 could have been observed. Either possibility would be of considerable interest, so although the reality of the burst has yet to be confirmed, afterglow searches are to be encouraged. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4168 SUBJECT: SGR 1806-20: continued moderate activity seen with INTEGRAL DATE: 05/10/27 08:09:41 GMT FROM: Sandro Mereghetti at IASF/CNR S. Mereghetti (IASF-Milano), D. Gotz (SAP, Saclay), M. Beck (ISDC, Versoix), J. Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team, and I.F. Mirabel (ESO) on behalf of the INTEGRAL Science Working Team report: The soft gamma-ray repeater SGR 1806-20 continues to be in an active bursting state. A few normal short bursts have been detected by IBAS in October 2005 (note that SGR 1806-20 was not observed continuously during this period; the INTEGRAL observation log can be found at http://intweb.esac.esa.int/ ). Burst times, approximate durations, and fluences (15-100 keV) measured with the IBIS/ISGRI instrument are reported below: Date and UT Duration (s) Fluence (erg cm-2) 2005-10-01T07:47:10 0.1 3E-8 2005-10-04T02:54:14 0.1 2E-8 2005-10-22T03:43:40 0.1 4E-8 2005-10-22T07:25:37 0.38 9E-7 2005-10-22T08:52:42 0.07 2E-8 2005-10-25T04:48:31 0.11 2E-8 The burst at 2005-10-22T08:52:42 was followed by a fainter peak 4.4 s later, lasting 0.04 s. We remind that the occurrence of SGR 1806-20 bursts detected with high signal to noise ratio is reported in real time with IBAS Alert Packets. See http://ibas.mi.iasf.cnr.it/ for an uptated table of all the IBAS Alerts and for information on how to receive the Alert Packets for soft repeaters and type I bursters. This message can be cited. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4197 SUBJECT: IPN triangulation and Konus spectrum of the bright short/hard GRB051103 DATE: 05/11/05 19:37:26 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and T. Cline on behalf of the Konus-Wind team, S. Barthelmy, J. Cummings, N. Gehrels on behalf of the Swift team, K. Hurley and T. Cline, on behalf of the Ulysses, HETE, Mars Odyssey, and Konus GRB teams, I. Mitrofanov, A. Kozyrev, M. Litvak, A. Sanin, V. Tret'yakov and A. Parshukov, on behalf of the HEND-Odyssey GRB team, W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr, on behalf of the GRS-Odyssey GRB team, D. M. Smith, R. P. Lin, J. McTiernan, R. Schwartz, C. Wigger, W. Hajdas, and A. Zehnder, on behalf of the RHESSI GRB team, J-L. Atteia, C. Graziani, and R. Vanderspek on behalf of the HETE team report: A very bright hard short GRB triggered the Konus-Wind instrument at T0=33943.785 s UT (09:25:43.785) on November 3. It was also observed by HETE-Fregate, Mars Odyssey (GRS and HEND), RHESSI, and Swift-BAT. We have triangulated this burst to the 3sigma confidence error box: RA(2000) Dec(2000) ---------------------------------------- ERROR BOX CENTER: 148.142 68.845 ERROR BOX CORNER 1: 148.563 69.189 ERROR BOX CORNER 2: 147.570 68.115 ERROR BOX CORNER 2: 147.731 68.499 ERROR BOX CORNER 4: 148.738 69.564 --------------------------------------- The area of the error box is 120 sq. arcmin. The error box is consistent with a source in M81. As observed by Konus-Wind the burst had a duration of 0.17 sec, fluence 2.34(-0.28, +0.31)10^-5 erg/cm2, and peak flux on 2ms time scale 1.89 (-0.35, +0.25)10^-3 erg/cm2/sec (both in 20 keV - 10 MeV range). The Epeak of the time-integrated spectrum is 1920 +/- 400 keV. Assuming this burst originated from a source in M81 (D = 4 Mpc), the isotrpoic energy release of this GRB is ~4.5x10^46 erg, which consistent with the energy release of 27 December giant flare from SGR 1806-20. The peak flux of this GRB is the largest ever observed for the Konus-Wind short GRBs. The burst light curve had a very steep rise ~4 msec and a decaying tail, similar to the initial pulses of SGR giant flares. All the quoted errors are at the 90% confidence level. The K-W light curve of this GRB and IPN triangulation map can be seen at http://www.ioffe.rssi.ru/LEA/GRBs/GRB051103_T33943/ /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4310 SUBJECT: Possible resuming of the SGR 1806-20 activity DATE: 05/12/03 14:37:11 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks on behalf of Konus-Wind, and T. Cline on behalf of the Konus-Wind team, Two SGR-like events were detected recently by the Konus-Wind. The first one triggered the Konus-Wind on December 1 at 35965.468 s UT (09:59:25.468) . It had a duration ~3.6 sec, a fluence ~2.0x10^-5 erg/cm2, a peak flux ~1.2x10^-5 erg/cm2 s (both in 20-200 keV range). The time-integrated spectrum of the burst is well fit by the OTTB spectral model: dN/dE ~ E^{-1} exp(-E/kT) with kT = 19.7 ± 0.6 keV, which is typical for SGR 1806-20. The second one occurred on December 3 at 32626.087 s UT (09:03:46.087) (only ~5 hours ago). It had an unusual long initial pulse with a duration ~9 sec followed by at least 9 weaker short bursts during the 229 sec of the Konus-Wind trigger record. So, this event can be classified as a burst series. The Konus-Wind spectral data for this event will be available in a day. The Konus ecliptic latitude response indicates that the source of these bursts is near the ecliptic plane. There were no solar flares at these times according to the GOES data. We suppose, that these events are originated from SGR 1806-20. But now we can not exclude the other possibilities. Further analysis using the data from other instruments will clarify this issue. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4312 SUBJECT: An extraordinary long burst on December 3 from SGR1806-20 DATE: 05/12/06 15:48:11 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and T. Cline on behalf of the Konus-Wind team, S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm on behalf of the Swift team, A bright extraordinary long SGR-like event triggered the Konus-Wind at T0=42203.684 s UT (11:43:23.684) on December 3. This burst was also observed by Swift-BAT out of the BAT field of view. The measured time delay between the burst arrival times on the two s/c is 5.245-5.276 sec (3 sigma confidence range). For the SGR 1806-20 position the expected time delay is 5.274 sec. As the measured time delay is consistent with the expected for the position of SGR 1806-20, we conclude that this burst originated from it. But we should notice that the measured time delay also consistent with the SGR 1801-23 position. The shape of the burst light curve was typical for SGR bursts, but with an unusually long duration. There was a short weak precursor ~0.3 sec long at T0-0.4 sec, followed by a 0.1 sec rise and a 22 sec decay. There was a weaker short soft burst at T-T0 ~110 sec. As observed by Konus-Wind the burst had a fluence (1.53+/-0.02)x10^-4 erg/cm2, and a peak flux on 16-ms time scale (3.50 ± 0.16)x10^-5 erg/cm2/sec (both in the 20-200 keV range). The time-integrated spectrum of the burst can be fit by the OTTB spectral model: dN/dE ~ E^{-1} exp(-E/kT) with kT = 19.9 + 0.5 keV, which is typical for SGR 1806-20. All the quoted errors are at 90% c.l. This is the longest SGR burst ever triggered the Konus-Wind. Despite its long duration there is apparently no periodicity in the light curve. The Konus-Wind light curve of this GRB can be seen at http://www.ioffe.rssi.ru/LEA/SGRs/051203_T42203/ Likely, the two previous unusually long SGR-like events detected by the Konus-Wind (Golenetskii et al., GCN 4310) originated from this SGR (both these events were not observed by the Swift-BAT because the SGR 1806-20 was below the horizon). BAT has since observed two short (~0.1 sec) bursts from SGR 1806-20, similar to many bursts seen earlier this year. Note, that the ~40-s long burst from SGR 1900+14 was detected on April 18, 2001 by BeppoSAX, and the Konus-Wind in the waiting mode (Guidorzi et al., 2004, A&A, 416, 297 and references therein). That event was strongly modulated with a 5-s period, but had the comparable fluence and peak flux. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4314 SUBJECT: IPN observations of SGR1806-20 DATE: 05/12/09 22:02:55 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses, Mars Odyssey, and Konus GRB teams, I. Mitrofanov, A. Kozyrev, M. Litvak, A. Sanin, V. Tret'yakov and A. Parshukov, on behalf of the HEND-Odyssey GRB team, W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr, on behalf of the GRS-Odyssey GRB team, S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, and D. Frederiks, on behalf of the Konus-Wind team, S. Barthelmy, J. Cummings, N. Gehrels, and H. Krimm, on behalf of the Swift team, A. von Kienlin, G. Lichti, A. Rau, D. Gotz, and S. Mereghetti, on behalf of the INTEGRAL GRB team, and D. M. Smith, R. P. Lin, J. McTiernan, R. Schwartz, C. Wigger, W. Hajdas, A. Zehnder, S. Boggs, and M. Bandstra, on behalf of the RHESSI GRB team, report: Various IPN spacecraft have observed the possible activity of SGR1806-20 (Golenetski et al. GCN Circ. 4310, 4312). The following table summarizes the results. DATE TIME REFERENCE ANNULUS CENTER ANNULUS RADIUS DISTANCE FROM SPACECRAFT SGR1801? GCN # RA DEC SGR1806-20 051201 35965 4310 216.911 -15.332 52.530+/-0.345 0.069 K,O,R No 051203 32626 4310 216.686 -15.337 52.647+/-0.275 0.161 K,O No 051203 42204 4312 273.814 -20.444 7.139+/-7.139 5.692 K,R,S,I Yes NOTES: The annulus center RA and Dec are J2000. The uncertainty in the radius is 3 sigma. The distance from SGR1806-20 is the distance between the center line of the annulus and the source, in degrees. The spacecraft are Konus (K), Odyssey (O), RHESSI (R), Swift (S), and INTEGRAL (I); Ulysses was off. SGR1801? indicates whether the IPN annulus is consistent with the position of SGR1801-23 (Cline et al., Ap.J. 531, 407, 2000). For the first event on 051203, SGR1806 and SGR1801 were Earth-occulted for RHESSI. The triangulation annulus (actually a circle) for the second event on 051203 is also consistent with the position of the bursting pulsar, GROJ1744-28. These localizations support the conclusion that the source of the first two events, and therefore probably the third also, is indeed SGR1806-20. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4946 SUBJECT: Konus-Wind observation of the recent SGR 1900+14 activity. Will DATE: 06/04/03 15:03:04 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks and T. Cline on behalf of the Konus-Wind team, report: Konus-Wind triggered twice on March 29 due to SGR 1900+14 activity. The first trigger occurred at 5282.959 s UT (01:28:02.959). This burst was detected and located by Swift BAT (Moretti et al., GCN 4933). It was an ordinary single spike SGR burst with a duration of ~0.07 sec. It had a fluence 7.21(-1.46,+0.91)x10^-7 erg/cm2 (in the 20-200 keV range). Its spectrum is well fitted by OTTB model with kT=18.3(-3.1,+3.7) keV. All the quoted errors are at the 90% confidence level. Much more interesting event triggered Konus-Wind at T0=9928.369 s UT (02:45:28.369). It was a series of bursts. The trigger part of the series contains seven intense bursts and several substantially weaker bursts. The fluences of the intense bursts vary from ~10^-7 to 1.5x10^-6 erg/cm2 (in the 20-200 keV range). At this time Swift was in SAA and did not detect these bursts. After the end of the Konus-Wind trigger record and during data read-out much more intense cluster of the bursts (observed and located by Swift-BAT (Romano et al., GCN 4934) was detected by Konus-Wind at T-T0=458 s (02:53:08) with coarse time resolution of 3.96 sec. As observed by Konus-Wind the cluster had a duration of ~25 sec. Fortunately, the multichannel spectra were accumulated by Konus-Wind during this cluster of bursts. We conservatively estimate the cluster fluence to be (1-2)10^-4 erg/cm2 (in the 20-200 keV range). This value can be refined. It is worth to notice that the reactivation of SGR 1900+14 in 1998 started with several single bursts, which were shortly followed by a series of bursts on 1998 May 30. (http://www.ioffe.rssi.ru/LEA/SGR/Catalog/Data/1900/980530a.htm ; Aptekar et al., ApJSS, 137, 227 (2001)) This series occurred 89 days before the 27 August 1998 giant flare. The first burst series from SGR 1806-20 was detected on 2004 October 5 by INTEGRAL-IBIS/ISGRI (Mereghetti et al., GCN 2763; Gotz, Mereghetti, and Mirabel, GCN 2764) and Konus-Wind (Golenetskii et al., GCN 2769), 83 days before the 27 December 2004 giant flare from this SGR. Other two series from SGR 1806-20 were detected by Konus-Wind on 2004 December 21 and 25. The March 29 series, considered here, resembles the burst series mentioned above, and has several times greater fluence. We conclude that at present time SGR 1900+14 demonstrates a behavior similar to pre-giant flare state. So we may expect a further increase activity of SGR 1900+14 and a repeated (!) giant flare from this SGR at the latter half of June. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5419 SUBJECT: GRB060806 = SGR1806-20 DATE: 06/08/07 21:26:55 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley, S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, D. M. Smith, R. P. Lin, J. McTiernan, R. Schwartz, C. Wigger, W. Hajdas, A. Zehnder, K.Yamaoka, M.Ohno, Y.Fukazawa, T.Takahashi, M.Tashiro, Y. Terada, T.Murakami, K.Makishima, S. Golenetskii, E. Mazets, V. Pal'shin, and D. Frederiks, report: The position of GRB060806 (Hurley et al. GCN 5416) is consistent with that of SGR1806-20, and the spectrum of this burst is soft. Therefore the origin of this event is almost certainly SGR1806-20, which has been active recently. This type of bursting behavior appears to be unique, however, so observations at other wavelengths are encouraged. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5426 SUBJECT: GRB060806 is similar to previous activity of SGR1806-20 DATE: 06/08/09 10:21:45 GMT FROM: Dmitry Frederiks at Ioffe Institute S.Golenetskii, D.Frederiks, V.Pal'shin, R.Aptekar, T.Cline and E.Mazets on behalf of the Konus-Wind team report: The soft gamma-ray event 060806 related to SGR1806-20 (Hurley et al., GCN 5416, 5419) is of great interest, However it hardly can be defined as unique for SGR1806-20, all of the main features of this event were also observed earlier. In 2006 SGR1806-20 renewed its activity in the middle of July. Until now it has emitted about 20 soft bursts. Date UT, s Instrument/Spacecraft Konus-Wind Konus-A (Cosmos-2421) 060717 50457 yes yes 060717 57178 yes no 060718 11636 yes no 640718 64171 no yes 060718 69585 yes yes 060721 61862 yes no 060728 30102 no yes 060729 76209 yes no 060731 27269 yes yes 060806 21037 yes yes 060806 51824 yes no 060807 3806 yes no 060807 5881 yes yes 060807 34982 yes no 060807 83305 yes no 060808 16377 yes no The GRB060806 composes a cluster of 6 separate bursts similar to clusters observed in 2004 on October 5, December 24 and 25. Energy spectra of all bursts in the table are identical, revealing the same value of kT = 20 +/- 0.5 keV. What is more, the last burst in the cluster, wich lasts for ~30 s and exhibits three broad pulses separated by time intervals of ~7.55 s, strikingly resembles the light curve of the soft burst from SGR 1806-20 occured on December 3, 2005. This burst also starts a quick growing spike followed by a long tail with two broad if less pronounced peaks of periodic pulsations. Date Duration Fluence Fmax kT sec erg cm-2 erg cm-2 s-1 keV 060806 30.8 2.4x10-4 4.7x10-5 20 051203 22 1.6x10-4 3.4x10-5 20 A comparative chart of the two events lightcurves one can find at: http://www.ioffe.ru/LEA/SGR/060806/0806-060806-051203.jpg /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5427 SUBJECT: VLA Upper Limit on Outburst of SGR 1806-20 DATE: 06/08/09 13:14:36 GMT FROM: Jim Ulvestad at NRAO E. Fomalont, B. Clark, and J. Ulvestad report on behalf of NRAO: We have used the NRAO Very Large Array in its B configuration on behalf of the community for an observation of SGR 1806-20, the apparent source of GRB 060806 (GCN 5416, Hurley et al. 2006; GCN 5419, Hurley et al. 2006). The observation epoch was 2006AUG09 at 03:15 UT. There was no significant detection of a new point source at the nominal J2000 position of 18:08:39.4, -20:24:39.8 (Taylor et al. 2005, ApJL, 634, L93). The approximate 5-sigma upper limits for a new point source are as follows: 1.42 GHz: < 2.0 mJy (limited by confusion) 8.46 GHz: < 0.3 mJy 22.46 GHz: < 1.7 mJy The raw data will appear in the VLA archive at http://www.nrao.edu/archive/ at approximately 0:00:00 UT on 2006AUG10, and are freely available to the community for further processing and analysis. An additional community observation is planned for 2006AUG10 to check for a later appearance of a new point source. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. [GCN OPS NOTE(09aug06): This Circular was delayed 8 hours until the new account could be added to the list.] /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5438 SUBJECT: A dust-scattering halo detected around SGR 1806-20 DATE: 06/08/11 16:27:31 GMT FROM: Kim Page at U.of Leicester M.R Goad, K.L. Page, O. Godet, P.T. O'Brien, S. Vaughan (U Leicester), and K. Hurley (Berkeley) report on behalf of the Swift-XRT team: Analysis of 2.5 ks of Swift-XRT Photon Counting (PC) mode data taken approximately 31 hours after the latest outburst of SGR 1806-20 (Hurley et al., GCN Circ. 5419), reveals a dust-scattering halo, with a angular radius of approximately 120 arcseconds at this time. The halo is also detected in 14 ks of XRT PC mode data taken 93.5 hours after the burst. The measured size of the halo at this time, approximately 212 arcseconds, is consistent with theoretical predictions for the expansion of a dust scattering halo. There are a number of well-known molecular clouds in the direction of SGR 1806-20 (eg. Corbel et al. 1997, ApJ 478, 624), including the so-called expanding arm located at a distance of approximately 3 kpc. Using simple geometrical arguments (eg. Predehl et al. 2000, A&A, 357, L25), we place a firm upper limit on the distance to the dust scattering screen of 6.6 kpc. Adopting as a lower limit the estimated distance to SGR 1806-20 of 6 kpc (McClure-Griffiths and Gaensler 2005, ApJL 630, L161), then the dust scattering screen is located at approximately 3 kpc, consistent with an origin in the expanding Arm. If, however, we adopt a distance of 15 kpc for SGR 1806-20 (Corbel et al. 1997), then the dust scattering screen is located at ~4.5 kpc. Another Soft Gamma-ray Repeater, SGR 1900+14, has previously shown a dust halo (Kouveliotou et al. 2001, ApJ 558, L47). /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5439 SUBJECT: Second VLA limit on new radio point source in SGR 1806-20 DATE: 06/08/11 21:13:35 GMT FROM: Jim Ulvestad at NRAO E. Fomalont, B. Clark, and J. Ulvestad report on behalf of NRAO: We have used the NRAO Very Large Array in its B configuration on behalf of the community for a second observation of SGR 1806-20, the apparent source of GRB 060806 (GCN 5416, Hurley et al. 2006; GCN 5419, Hurley et al. 2006). As noted in GCN 5426 (Golenitskii et al. 2006), the gamma-ray activity is far below that of the large flare of December 2004. The observation epoch for the second VLA observation was 2006AUG11 at 06:10 UT, and there was no detection of a new radio point source at the location of SGR 1806-20. The approximate 5-sigma upper limit at 8.46 GHz was < 0.23 mJy, consistent with the value of < 0.30 mJy seen two days previously and reported by us in GCN 5427. This concludes the planned NRAO service observations of SGR 1806-20 in response to the recent outburst. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5440 SUBJECT: Image of the dust-scattering halo around SGR 1806-20 DATE: 06/08/12 08:31:07 GMT FROM: Kim Page at U.of Leicester K.L. Page (U. Leicester) & N. Gehrels (NASA/GSFC) report on behalf of the Swift-XRT team: As an addendum to yesterday's GCN Circular (number 5438) about the detection of a dust-scattering halo around SGR 1806-20, please find available an image of the expanding halo at: http://www.swift.ac.uk/SGR1806.shtml /////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5490 SUBJECT: Two bright bursts from SGR 1806-20 detected with IBAS DATE: 06/08/30 15:48:59 GMT FROM: Diego Gotz at IASF-CNR D. Gotz (CEA, Saclay) and S. Mereghetti (IASF, Milano), on behalf of the IBAS Localization Team report: The INTEGRAL Burst Alert System (IBAS) has detected several bursts from SGR 1806-20 in the IBIS/ISGRI data, indicating that the source is in an active state. We report here the properties of the two brightest and longest bursts, that were detected on August 29, 2006, as well as the times of the other events detected in the last few days. The burst detected on Aug 29 at 21:57:43 UT was so bright to fully saturate the ISGRI telemetry share after about 1 s. This burst was also detected by the Anti-Coincidence System of the SPI instrument above ~80 keV, where it lasted 2 s. The 20-200 keV spectrum, derived from the the available IBIS/ISGRI data, can be fitted with a Thermal Bremsstrahlung (TB) model with a temperature of 22 keV. This is a typical value for the SGR 1806-20 bursts, but the lower limit on its fluence ( 7E-7 erg/cmsq, 15-100 keV) places this burst among the brightest detected with INTEGRAL (Gotz et al., 2006, A&A, 445, 313). The second burst was detected at 22:10:28 UT and lasted 1.2 s. In this case the telemetry was saturated only partially. The lower limit on the fluence is 1E-6 erg/cmsq, and the TB temperature is 19 keV. The times of all the recent IBAS triggers due to bursts from SGR 1806-20 are given below. For 15 of them automatic alert packets have been sent (see Alerts #3437-3452 at http://ibas.iasf-milano.inaf.it). 2006-08-19T05:57:48 2006-08-25T21:03:31 2006-08-26T02:13:37 2006-08-26T03:23:35 2006-08-26T04:13:22 2006-08-26T04:25:25 2006-08-26T12:32:55 2006-08-26T18:48:47 2006-08-26T22:07:52 2006-08-27T03:14:45 2006-08-27T04:20:10 2006-08-27T08:49:52 2006-08-27T12:25:26 2006-08-27T12:41:34 2006-08-28T13:38:31 2006-08-29T21:57:43 2006-08-29T22:10:28 2006-08-29T22:48:01 2006-08-30T03:16:47 2006-08-30T14:58:39 2006-08-30T15:11:34 INTEGRAL will continue to monitor regularly the region of the Galactic Centre (at least once every 3 days) until October 26th. This message can be cited. /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6013 SUBJECT: Further Retractions of previous Swift-BAT triggers DATE: 07/01/12 14:50:25 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC) on behalf of the Swift-BAT Team This adds to and amends GCN Circ 5987 (Barthelmy) to complete the corrections to the trigger type identifications for previous Swift-BAT triggers. The table below contains the Trigger Number, the Trigger Date and Time, and a Comment about what we are currently classifying the trigger. TRIGNUM DATE TIME DESCRIPTION 102899 05 Jan 17 20:03:36 We originally issued GCN Circ 2959 which called it GRB 050117B, but we now classify this as an SAA-induced noise event. 131395 05 Jun 02 10:41:45 This was classified in GCN Circ 5987 as "S/C drifting in Sun_Reference Safe_Hold mode", but we now believe the s/c attitude was correctly known thus making the identification SGR1806-20 solid; and further, there is temporal coincidence with a HETE detection (K.Hurley, private communication). 158539 05 Oct 06 13:52:40 This was originally classified as EXO 0748-676 in the real-time Notices, but we now classify this as a chance coincidence of noise in the rate and image domains with the location of EXO 0748-676. 213190 06 Jun 02 23:54:34 This was called "GRB060602B (or possibly an XRB)" in GCN Circ 5208, but we now believe this to be an x-ray burster source with a high confidence level. /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6094 SUBJECT: GRB 070201: clarification on localization and Konus-Wind spectra DATE: 07/02/10 17:21:40 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and T. Cline on behalf of the Konus-Wind team report: The ecliptic latitudes band of GRB 070201 was given incorrectly in GCN 6088. The correct band is +30 +90 deg. The coordinates of the portion of the Wind-INTEGRAL annulus reported in GCN 6088 and the map posted at http://www.ioffe.rssi.ru/LEA/GRBs/GRB070124_T31311/ are correct (more accurate coordinates of the intersection the ecliptic latitude lower limit (+30) with the center of the annulus are RA, Dec = 13.471, +38.601 deg). We apologize for the confusion and thank Derek Fox, Eran Ofek, and Daniel Perley for pointing out the error. As was noted by Perley and Bloom (GCN 5947) the burst location area includes the M31 galaxy's outer spiral arms. The position of NGC 5985 galaxy suggested by Ofek (GCN 6092) is definitely out of the burst location area. The confusion was caused by the error in the reported ecliptic latitude band. Preliminary analysis shows that the burst had a fluence of 1.57(-0.21, +0.06)x10^-5 erg/cm2, and the 2-ms peak flux measured from T0+0.016 s 9.4(-2.9,+1.7)x10^-4 erg/cm2/s (both in the 20 keV - 1 MeV energy range). Assuming this burst originated from a source in M31 (D ~770 kpc), the isotrpoic energy release would be ~1x10^45 erg, which is between the energy release in initial pulse of the 5th March 1979 giant flare from SGR 0526-66 (~2x10^44 erg) and the 27th December 2004 giant flare from SGR 1806-20 (~2x10^46 erg). The time-integrated spectrum of the burst (from T0 to T0+0.256 s) is well fitted (in the 20 keV - 1 MeV range) by a power law with exponential cutoff model: dN/dE ~ E^(-alpha)*exp(-E*(2-alpha)/Ep) with alpha = 0.98(-0.11, +0.10) and Ep = 293 (-31, +38) keV (chi2 = 39/40 dof). The spectrum of the burst maximum (from T0 to T0+0.064 s) is well fitted (in the 20 keV - 1 MeV range) by a power law with exponential cutoff model: dN/dE ~ E^(-alpha)*exp(-E*(2-alpha)/Ep) with alpha = 0.52(-0.15, +0.14) and Ep = 357 (-38, +44) keV (chi2 = 39/40 dof). All the quoted errors are at the 90% confidence level. Due to large uncertainties in the burst position and large dead times caused by very high count rates these values should be considered only as preliminary. /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6228 SUBJECT: long burst from SGR 1806-20 detected on March 26 DATE: 07/03/28 13:02:07 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and T. Cline on behalf of the Konus-Wind team, K. Yamaoka, T. Uehara, M. Ohno, Y. Fukazawa, T. Takahashi, M. Tashiro, Y. Terada, T. Murakami, and K. Makishima on behalf of the Suzaku WAM team, report: A bright long SGR-like event triggered the Konus-Wind at T0=1447.725 (00:24:07.725) on March 26. It was also detected by the Suzaku-WAM in the TRN mode. We have triangulated it to an annulus centered at RA(J2000) = 186.083 (12h 24m 20s) Dec(J2000)=+3.334 (+3d 20' 04"), whose radius is 87.186 +/- 1.090 deg (3 sigma). As the center line of this annulus passes 0.311 degrees (0.9 sigma) from the position of SGR 1806-20 and the Konus ecliptic latitude response indicates that the source of the burst is near the ecliptic plane, we believe that this burst originated from SGR 1806-20. The shape of the burst light curve is typical for SGR bursts, but with an unusually long duration. It demonstrates a fast rise and a ~8-s decay with a bump at T-T0 ~5 s. As observed by Konus-Wind the burst had a fluence 2.78(-0.08, +0.07)x10^-5 erg/cm2, and a peak flux on 16-ms time scale 2.01(-0.26, +0.25)x10^-5 erg/cm2 (both in the 20-200 keV range). The time-integrated spectrum of the burst can be fit by the OTTB spectral model: dN/dE ~ E^{-1} exp(-E/kT) with kT = 20.7 +/- 0.7 keV, which is typical for SGR 1806-20. All the quoted errors are at 90% c.l. The Konus-Wind light curve of this GRB can be seen at http://www.ioffe.rssi.ru/LEA/SGRs/070326_T01447/ A previous SGR burst triggered Konus-Wind on March 17 at T0=84623.793 s UT (23:30:23.793). It had a duration of ~4 sec. The burst was not localized, but since the Konus ecliptic latitude response indicates that the burst source is near the ecliptic plane, we believe that it also originated from SGR 1806-20. The longest burst from SGR 1806-20 (except the giant burst) had a duration of ~22 sec (Golenetskii et al., GCN 4312). /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6239 SUBJECT: INTEGRAL ToO Observation of SGR1806-20 DATE: 07/04/02 17:03:03 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley, on behalf of the INTEGRAL AO-4 SGR ToO team, reports: In view of the recent activity of SGR1806-20 observed by Konus (GCN 6228), as well as a lower level of activity observed by Swift, we have called an INTEGRAL target of opportunity observation of this source. The start times and durations of the observations are: Start time, UT Duration (s) 2007-04-06 11:33:21.0 109728 2007-04-07 19:31:06.0 44577 2007-04-08 08:40:42.0 24003 2007-04-08 16:06:00.0 30861 We encourage supporting observations at all wavelengths. /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6264 SUBJECT: Suzaku ToO observation of SGR 1806-20 DATE: 07/04/10 09:45:07 GMT FROM: Yujin E. Nakagawa at Aoyama Gakuin U Y. E. Nakagawa, K. Yamaoka, A. Yoshida, S. Sugita (Aoyama Gakuin U.), T. Mihara (RIKEN), M. Suzuki (ISAS/JAXA), T. Murakami, D. Yonetoku (Kanazawa U.), M. Nakajima (Nihon U.), M. Tashiro (Saitama U.), and K. Nakazawa (Univ. of Tokyo) report: The Suzaku ToO Observation was conducted on SGR 1806-20 with the narrow field instruments (XIS and HXD) from 15:08:00 on March 30 2007 to 01:30:19 on March 31. Its net exposure was about 20 ks. This object showed a long burst at 00:24:08 on March 26 2007 which was detected by the Konus-Wind and the Suzaku-WAM instruments (Golenetskii et al., GCN 6228). No bright burst was observable in the light curve during the ToO observation. The preliminary analyses showed that the flux of the steady emission in 2-10 keV was about 8.8 x 10^-12 ergs cm^2 s^-1. By the quick-look analyses with the XIS data, the average spectrum is well fitted by a single power-law model of the photon index of ~ 2.1 with an interstellar absorption column of ~ 7 x 10^22 cm^-2, as well as a two blackbody function is acceptable. We would like to thank the Suzaku team for the immediate ToO observation and the data processing. /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6684 SUBJECT: Intense burst from SGR 1806-20 detected on July 27 DATE: 07/07/29 18:50:55 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and T. Cline on behalf of the Konus-Wind team, A. von Kienlin, G. Lichti, A. Rau, D. Gotz, and S. Mereghetti, on behalf of the INTEGRAL GRB team, K. Yamaoka, T. Uehara, M. Ohno, Y. Fukazawa, T. Takahashi, M. Tashiro, Y. Terada, T. Murakami, and K. Makishima on behalf of the Suzaku WAM team, K. Hurley, D. M. Smith, R. P. Lin, J. McTiernan, R. Schwartz, C. Wigger, W. Hajdas, and A. Zehnder, on behalf of the RHESSI GRB team, report: An intense short SGR-like event triggered Konus-Wind at 2007-07-27 T0=24046.498 s UT (06:40:46.498). It was also detected by INTEGRAL-SPI-ACS, RHESSI, and Suzaku-WAM in the TRN mode. We have triangulated this burst to Konus-SPI-ACS and Konus-RHESSI annuli, both of which are consistent with the position of SGR 1806-20. The Konus-SPI-ACS annulus is inconsistent with the positions of all other known SGRs. The Konus ecliptic latitude response indicates that the source of the burst is near the ecliptic plane. Thus we believe that this burst originated from SGR 1806-20. The burst had a duration of ~1 s. The Earth-crossing time of the onset was 24041 s UT (06:40:41). As observed by Konus-Wind the burst had a fluence of 9.14(-0.44, +0.36)x10^-6 erg/cm2, and a 16-ms peak flux measured from T0-0.050 s of (1.91 +/- 0.25)x10^-5 erg/cm2 (both in the 20-200 keV range). The spectrum of the burst (from T0 to T0+0.256) is well fitted (in the 20-200 keV range) by the OTTB spectral model: dN/dE ~ E^{-1} exp(-E/kT) with kT = 21.7 +/- 1.2 keV (chi2 = 25/20 dof). All the quoted errors are at 90% c.l. The Konus-Wind light curve of this burst is available at http://www.ioffe.rssi.ru/LEA/SGRs/070727_T24046/ The last burst from SGR 1806-20 to trigger Konus-Wind was on March 26 (Golenetskii et al., GCN 6228). /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6688 SUBJECT: AGILE-ACS position for the SGR 1806-20 July 27 burst DATE: 07/07/30 16:25:36 GMT FROM: Sandro Mereghetti at IASF/CNR F.Perotti, A.Giuliani, S.Mereghetti, M.Fiorini, S.Vercellone, A.Chen, A.Pellizzoni (IASF-Milano), C.Labanti, M.Trifoglio, G.Di Cocco (IASF-Bologna), M.Tavani, M.Feroci, A.Argan, A.Trois (IASF-Roma), G.Picozza (INFN-Roma), F.Longo, G. Barbiellini (INFN-Trieste), on behalf of the AGILE Team and P. Giommi, L.A. Antonelli, C. Pittori (ASDC), and L. Salotti (ASI) report: The SGR-like burst detected on July 27 at about 06:41 UT with Konus/Wind, INTEGRAL-SPI-ACS, RHESSI and Suzaku-WAM (Golenetskii et al. GCN 6684), and likely associated to SGR 1806-20, has been seen also by the Anticoincidence system of AGILE. This segmented anticoincidence detector surrounds the gamma-ray tracker on five sides (top and 4 lateral). The relative intensity of the count rates measured from the different sides allows to estimate the arrival direction of the detected bursts. Based on a simple geometrical model, the detection of this event in two of the lateral panels and its non-detection in the top panel, yields an instrumental azimuthal angle within 3 degrees from that of SGR 1806-20. We thus support the association of this event with SGR 1806-20. /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6775 SUBJECT: Intense burst from SGR 1806-20 detected on September 7 DATE: 07/09/10 16:59:15 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and T. Cline on behalf of the Konus-Wind team, J. Cummings, S. Barthelmy, N. Gehrels, H. Krimm, and D. Palmer on behalf of the Swift-BAT team, K. Hurley, A. von Kienlin, G. Lichti, A. Rau, D. Gotz, and S. Mereghetti, on behalf of the INTEGRAL GRB team, report: An intense, short SGR-like event triggered Konus-Wind at 2007-09-07 T0=60387.314 s UT (16:46:27.314). It was also detected by Swift-BAT (out FoV) and INTEGRAL-SPI-ACS. It was not detected by any other IPN spacecraft. We have triangulated this burst to the Konus-BAT annulus centered at RA(2000)=330.018 (22h 00m 04s) Dec(2000)=-7.254 (-7d 15' 14"), whose radius is 57.445 +/- 0.407 deg (3 sigma) and to the Konus-SPI-ACS annulus centered at RA(2000)=328.332 (21h 53m 20s) Dec(2000)=-1.259 (-1d 15' 31"), whose radius is 58.080 +/- 0.653 deg (3 sigma). The center lines of these annuli pass 0.041 deg from the position of SGR 1806-20 (correspondingly 0.3 and 0.2 sigma). They are inconsistent with the positions of all other known SGRs. The Konus ecliptic latitude response indicates that the source of the burst is near the ecliptic plane. Thus we conclude that this burst originated from SGR 1806-20. The burst light curve shows a ~30-ms long spike at T-T0 ~-0.240 s followed by the main pulse with a duration of ~2 s, and a small hump at T-T0 ~5.9 s with a duration of ~100 ms. The Earth-crossing time of the first spike was 60384.6 s UT (16:46:24.6). As observed by Konus-Wind the burst had a fluence of 1.47(-0.05, +0.04)x10^-5 erg/cm2, and a 16-ms peak flux measured from T0+0.016 s of (1.67 +/- 0.21)x10^-5 erg/cm2 (both in the 20-200 keV range). The spectrum of the burst (from T0 to T0+8.448) can be fitted (in the 20-200 keV range) by the OTTB spectral model: dN/dE ~ E^{-1} exp(-E/kT) with kT = 20.9 +/- 0.9 keV (chi2 = 36/27 dof). All the quoted errors are at 90% c.l. The Konus-Wind light curve of this burst is available at http://www.ioffe.rssi.ru/LEA/SGRs/070907_T60387/ The last burst from SGR 1806-20 to trigger Konus-Wind was on July 27, 2007 (Golenetskii et al., GCN 6684). Additional smaller bursts have been detected by BAT at 2007-09-09 22:45:36 and 2007-09-10 05:31:06 UT. /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6804 SUBJECT: SGR1806-20: Swift-BAT detection of enhanced activity DATE: 07/09/19 21:29:28 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), D. M. Palmer (LANL), T. Sakamoto (NASA/ORAU), G. Sato (GSFC/ISAS) and M. Stamatikos (NASA/ORAU) report on behalf of the Swift Team: At 20:45:10 UT, the Swift Burst Alert Telescope (BAT) triggered and located the SGR 1806-20 (trigger=291587). We note that the initial GCN Notice went out with a dual identification of this source (both SGR 1900+14 and SGR 1806-20). This is due to a mismatch error in the catalog numbers used between the on-board and ground catalogs for this source. The real identification is SGR 1806-20. We also note that because of a star tracker loss-of-lock error, the flight position is 10 arcmin off the true position. The BAT light curve shows a large initial spike of ~190,000 counts/sec with an ~2 sec FWZM, followed by 4 smaller spikes: ~2000 cnts/sec at ~T+3 sec, 10,000 cnts/sec at ~T+5 sec, 50,000 cnts/sec at ~T+14 sec, and 30,000 cnts/sec at ~T+18 sec. Swift-BAT, and other space instruments (e.g. Konus-WIND and Konus-A, Suzaku-WAM, IBAS, and SuperAGILE) have been detecting elevated activity from this source over the past few days. Notably, earlier today (at 16:01:12 UT, Trigger #291566) a 50,000 counts/second burst (250 times the flux of the Crab) was detected by BAT, which made it the third largest SGR 'baby' burst (excluding activity related to the superburst) imaged by the Swift mission. The new Trigger #291587 burst reported here is much larger. /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6815 SUBJECT: INTEGRAL ToO observations of SGR1806-20 DATE: 07/09/21 23:23:49 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley, on behalf of the INTEGRAL Cycle 4 SGR ToO team, reports: In view of the continued activity of SGR1806-20, a 206 ks INTEGRAL Target of Opportunity observation of this source has been scheduled. The tentative observation times are: Start time Duration (s) 2007-09-30 00:06:42.0 106299 2007-10-01 07:04:45.0 48006 2007-10-01 21:20:21.0 24003 2007-10-02 04:42:45.0 27432 Any major changes to these times will be reported in a future GCN. Supporting observations at all wavelengths are encouraged. /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6822 SUBJECT: Recent SGR1806-20 Activity DATE: 07/09/24 20:45:04 GMT FROM: Kevin Hurley at UCBerkeley/SSL S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P. Oleynik, M. Ulanov and T. Cline, on behalf of the Konus-Wind and Konus-A teams, D. Palmer, S. Barthelmy, J. Cummings, N. Gehrels, and H. Krimm, on behalf of the Swift-BAT team, K. Hurley, A. von Kienlin, G. Lichti, A. Rau, D. Gotz, and S. Mereghetti, on behalf of the INTEGRAL GRB team, M. Feroci, P. Soffitta and Y. Evangelista, on behalf of the AGILE team, K. Yamaoka, M. Ohno, Y.E. Nakagawa, Y. Fukazawa, T. Takahashi, M. Tashiro, Y. Terada, T. Murakami, and K. Makishima, on behalf of the Suzaku WAM GRB team, report: SGR1806-20 has become very active since September 14 (Barthelmy et al. GCN 6804). The following is a partial list of bursts observed by some of the IPN spacecraft (some weaker IBIS events did not trigger the INTEGRAL Burst Alert Service). "Loc" means that the burst was localized by triangulation to at least a relatively narrow annulus, or by the Swift BAT or by IBIS. A "no" in this column means that the event has only been localized to a relatively wide ecliptic latitude band. INTEGRAL (GCN 6815) and Chandra target of opportunity observations of this source are planned, and we encourage supporting observations at all wavelengths. Date Time Fluence Observed by Loc 20-200 (at least) keV ------------------------------------------------------------------- 20070914 10:46:02 8.2E-7 BAT,IBIS,KW y 20070914 14:54:47 1.6E-5 KW,KA,SA y 20070914 14:58:44 1.0E-6 KW no 20070914 19:57:57 2.8E-6 BAT,KA y 20070914 21:03:36 4.5E-7 KW no 20070916 07:08:38 6.5E-7 IBIS,KW y 20070916 09:48:08 1.0E-6 IBIS,KW y 20070918 17:08:50 1.6E-5 KW,SA,SPI-ACS,SUZ y 20070919 10:01:51 1.5E-6 IBIS,KW y 20070919 15:13:04 6.5E-7 KW no 20070919 16:01:13 2.4E-6 BAT,KA,KW y 20070919 16:54:44 9.6E-7 KW no 20070919 19:34:50 9.0E-7 IBIS,KW y 20070919 20:45:10 ? BAT,IBIS y 20070920 04:30:11 1.9E-6 IBIS,KW y 20070921 07:11:59 1.4E-6 IBIS,KW y 20070921 11:45:35 4.0E-7 KW no 20070923 12:46:15 2.6E-6 KW,KA no ------------------------------------------------------------------ Some Abbreviations: BAT: Swift Burst Alert Telescope IBIS: Imager on Board the INTEGRAL Satellite KA: Konus-A (Cosmos 2421) KW: Konus-Wind SA: Super-AGILE SPI-ACS: Anticoincidence System of the INTEGRAL Spectrometer SUZ: Suzaku WAM /////////////////////////////////////////////////////////////// quiet interval /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8497 SUBJECT: SGR 1806-20: Fermi GBM detection DATE: 08/11/07 17:26:47 GMT FROM: Sheila McBreen at MPE Sheila McBreen (UCD/MPE) and Chryssa Kouveliotou (NASA/MSFC) report on behalf of the Fermi GBM Team: "At 05:47:04.08 UT on 06 November 2008, the Fermi Gamma-Ray Burst Monitor triggered on a soft, short event (trigger 247643225 / 081106241). The on-ground calculated location, using the GBM trigger data, is RA = 271.3, DEC = -16.2 (J2000 degrees, equivalent to 18 h 05 m, -16 d 12 '), with an uncertainty of 5.6 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error for soft localisations which is currently estimated to be 5 to 6 degrees). This position is consistent with SGR 1806-20. The angle from the Fermi LAT boresight is 41 degrees. The GBM light curve comprises a single peak with a duration of about 80 ms. The time-averaged spectrum from T0-0.045 s to T0+0.035 s is adequately fit by a simple power law function with index -2.13 +/- 0.08. (chi squared 205.1, for 242 d.o.f.) The event fluence (10-100 keV) in this time interval is (7.9 +/- 0.3)E-8 erg/cm^2. An optically thin thermal bremsstrahlung (OTTB) function fits the spectrum equally well (chi squared 203.9 for 242 d.o.f.) with kT = 36.5 +/-3.9 keV. The spectral analysis results presented above are preliminary, Final results will be published in the GBM Magnetar catalog." /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8580 SUBJECT: SGR 1806-20: Fermi GBM detection. DATE: 08/11/29 17:52:19 GMT FROM: Valerie Connaughton at MSFC Valerie Connaughton (UAH) and Chryssa Kouveliotou (NASA/MSFC) report on behalf of the Fermi GBM Team: "At 00:38:12.71 UT on 29 November 2008, the Fermi Gamma-Ray Burst Monitor triggered on a short, soft event (trigger 249611893 / 081129027). The GBM on-ground location is consistent with the Soft Gamma Repeater SGR 1806-20. A preliminary estimate of the duration (128 ms) and count spectrum of the event reinforce its association with the repeater source. This is the second recent Fermi GBM-triggered event from SGR 1806-20, the first having occurred on 06 November 2008 (GCN 8497, McBreen and Kouveliotou). The angle from the Fermi LAT boresight is 118 degrees. Detailed timing and spectral analysis are in progress." /////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10549 SUBJECT: Fermi/GBM and Swift/BAT detection of a burst from SGR 1806-20 DATE: 10/03/29 13:36:33 GMT FROM: Narayana Bhat at U Alabama/Huntsville/GBM P. N. Bhat (UAHuntsville), David Palmer (Los Alamos National Laboratory), Chryssa Kouveliotou (NASA/Marshall Space Flight Center) and Scott Barthelmy (NASA/Goddard Space Flight Center) report on behalf of a larger collaboration: "The Fermi/Gamma-Ray Burst Monitor (GBM) triggered on 2010 March 26 at 20:48:59.86 UT on the SGR-like event 100326 (trigger 291329341 / 100326867). The on-ground calculated location, using the GBM trigger data, is RA = 265.93, DEC = -22.09 (J2000 degrees, equivalent to 17h 43.7m, -22d 5.4'), with an uncertainty of 4.5 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The GBM location includes the position of at least two SGR sources: the confirmed SGR 1806-20 and the candidate SGR 1801-23. The GBM burst light curve shows one pulse with a duration of about 100 ms (25-50 keV). The angle from the Fermi LAT boresight is 45 degrees. The time-averaged spectrum from T0-0.064s to T0+0.048 s is well fit by a power law function with an exponential high energy cutoff. The power law index is -0.40 (+/-0.31) and the cutoff energy, parameterized as Epeak, is 33.50 (+/- 1.94) keV (CSTAT 468 for 508 d.o.f.). The event fluence (8-1000 keV) in this time interval is (7.88 +/- 0.39)E-07 erg/cm^2. The 32-msec peak photon flux measured starting from T0+0 s in the 10-1000 keV band is 16.38 +/- 0.78 ph/s/cm^2. The Swift/Burst Alert Telescope (BAT) also detected GBM100326.867 but the image significance was not above threshold. BAT located the event to within 1 arcminute of SGR 1806-20, which we conclude is the origin of the burst emission. This is the first burst that BAT has detected from this source since since 2010, February 10, and the largest since 2007, November 9. The spectral analysis results presented above are preliminary. /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11407 SUBJECT: Fermi GBM detection of a burst from a galactic source DATE: 10/11/15 16:45:48 GMT FROM: Alexander van der Horst at NASA/MSFC A.J. van der Horst (USRA) and C. Kouveliotou (NASA/MSFC) report on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 311450068 at 17:54:26.74 UT on 14 November 2010, tentatively classified as Unreliable Location, is in fact a short, soft burst from a galactic source. The on-ground location, using the GBM trigger data, is RA = 264.3, Dec = -20.9 (J2000 degrees, equivalent 17h37m to -20d52m), with an uncertainty of 5.3 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). This location corresponds to galactic coordinates: Long = 5.88, Lat = 5.85 (J2000 degrees). The angle from the LAT boresight is 55 degrees. The GBM light curve consists of one peak with an estimated duration of 32 ms (8-1000 keV). The time-averaged spectrum from T0-0.032 s to T0 is best fit by Optically Thin Thermal Bremsstrahlung with Epeak = 28.4 +/- 2.2 keV. The event fluence (10-1000 keV) in this time interval is (5.4 +/- 0.3)E-8 erg/cm^2. The 16-ms peak photon flux measured starting from T0-0.016 s in the 10-1000 keV band is 61.9 +/- 3.2 ph/s/cm^2. The location, duration and spectrum of the source indicate that this is a burst from a source in the galactic center region, typical of a magnetar burst. We suggest that this is a burst from SGR 1806-20, but the location uncertainty is too large to draw any firm conclusions on its nature. The temporal and spectral analysis results presented above are preliminary." /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11909 SUBJECT: GRB 110406A: Positional coincidence with NGC 404 DATE: 11/04/08 15:43:53 GMT FROM: Antonia Rowlinson at U.of Leicester A. Rowlinson, P.T. O'Brien, N.R. Tanvir (U. Leicester) and A.J. Levan (U. Warwick) report: We note that the the error box of the bright short hard GRB 110406A detected by INTEGRAL SPI-ACS and the IPN (GCNs 11890, 11893, 11900) overlies NGC 404, a dwarf galaxy at a distance of ~3 Mpc. The IPN error box and the extent of NGC 404 are overlayed on a GALEX FUV image here: http://www.star.le.ac.uk/~bar7/NGC404_FUV.jpg NGC 404 is a recently rejuvinated lenticular galaxy, forming the majority of its new stars in a ring with a star formation rate of 2.5e-3 M_sol yr^-1 (Thilker et al., 2010, ApJ, 714, L171). If this GRB is associated with NGC 404, the isotropic energy released would be ~6e46 erg (20 keV - 10 MeV) using the Konus-Wind spectral fit (GCN 11893) which would be consistent with an SGR giant flare origin, while the presence of a young stellar population within this galaxy would also be consistent with this model. For comparison, the giant flare from SGR 1806-20 had Eiso ~3.7e46 erg (Hurley et al., 2005, Nature, 434, 1098). /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12958 SUBJECT: Fermi GBM detection of an SGR-like burst DATE: 12/02/15 10:19:00 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: "At 09:07:49.67 UT on 07 February 2012, the Fermi Gamma-Ray Burst Monitor triggered on a soft, short event (trigger 350298471 / 120207380). The event was tentatively classified as a solar flare, but it may be a burst from a Galactic source, most likely the soft gamma repeater SGR 1806-20. The on-ground calculated location, using the GBM trigger data, is RA = 270.0, DEC = -24.5 (J2000 degrees, equivalent to 18 h 00 m, -24 d 30 '), with an uncertainty of 3.9 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). This location corresponds to Galactic coordinates: Long = 8.9, Lat = -6.9 (J2000 degrees), consistent with the position of SGR 1806-20 and other known SGRs in that region. We conclude that this burst is either coming from one of these sources or from a new, yet unknown source. The angle from the Fermi LAT boresight is 80 degrees. The GBM light curve shows a single peak with a duration of about 150 ms. The time-averaged spectrum from T0-0.032 s to T0+0.096s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.04 +/- 0.31 and the cutoff energy, parameterized as Epeak, is 25.5 +/- 1.2 keV. The event fluence (10-1000 keV) in this time interval is (1.9 +/- 0.1)E-07 erg/cm2. The temporal and spectral analysis results presented above are preliminary." /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13237 SUBJECT: Trigger 519868: Swift detection of SGR1806-20 DATE: 12/04/10 23:23:06 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), P. D'Avanzo (INAF-OAB), N. Gehrels (NASA/GSFC), E. A. Hoversten (PSU), C. B. Markwardt (NASA/GSFC) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 23:08:33 UT, the Swift Burst Alert Telescope (BAT) triggered and located an outburst from SGR1806-20 (trigger=519868). Swift did not slew because of the Moon observering constraint. The BAT on-board calculated location is RA, Dec 272.153, -20.410 which is RA(J2000) = 18h 08m 37s Dec(J2000) = -20d 24' 35" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single spike with a duration of about 0.2 sec. The peak count rate was ~13,000 counts/sec (15-350 keV), at ~0 sec after the trigger. Due to an observing constraint Swift will be unable to observe this field with the XRT and UVOT instruments until 12 April at 14:00 UT. /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13239 SUBJECT: SGR1806-20, Swift-BAT refined analysis (Trigger 519868) DATE: 12/04/11 12:36:01 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from recent telemetry downlinks, we report further analysis of the outburst from SGR1806-20 (trigger #519868) (Barthelmy, et al., GCN Circ. 13237). The BAT ground-calculated position is RA, Dec = 272.163, -20.405 deg, which is RA(J2000) = 18h 08m 39.1s Dec(J2000) = -20d 24' 19.0" with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 16%. The mask-weighted light curve shows a single spike starting at ~T-0.002 sec, peaking at ~T+0.003 sec, and ending at ~T+0.15 sec with a tail out to ~T+0.4 sec. T90 (15-350 keV) is 0.77 +- 0.32 sec (estimated error including systematics). The time-averaged spectrum from T-0.06 to T+0.96 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.77 +- 0.15. The fluence in the 15-150 keV band is 5.1 +- 0.4 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T-0.08 sec in the 15-150 keV band is 10.7 +- 0.9 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/519868/BA/ /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13844 SUBJECT: Trigger 535747: Swift detection of an outburst from SGR1806-20 DATE: 12/10/11 03:13:02 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), S. T. Holland (STScI) and J. A. Kennea (PSU) report on behalf of the Swift Team: At 02:54:21 UT, the Swift Burst Alert Telescope (BAT) triggered and located an outburst from SGR 1806-20 (trigger=535747). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 272.130, -20.410 which is RA(J2000) = 18h 08m 31s Dec(J2000) = -20d 24' 35" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single spike with a duration of about 0.064 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~0.0 sec after the trigger. The XRT began observing the field at 02:55:19.9 UT, 58.6 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source with an enhanced position: RA, Dec 272.1635, -20.4112 which is equivalent to: RA(J2000) = 18h 08m 39.24s Dec(J2000) = -20d 24' 40.3" with an uncertainty of 4.1 arcseconds (radius, 90% containment). This location is 113 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 1.4 arcseconds from that of SGR 1806-20. A power-law fit to a spectrum formed from promptly downlinked event data does not constrain the column density. UVOT took a finding chart exposure of 150 seconds with the White filter starting 63 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers none of the XRT error circle. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13851 SUBJECT: Swift-BAT refined analysis of the SGR 1806-20 outburst (trigger 535747) DATE: 12/10/11 20:59:24 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), S. T. Holland (STScI), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+807 sec from recent telemetry downlinks, we report further analysis of BAT trigger (#535747) from SGR1806-20 (Barthelmy, et al., GCN Circ. 13844). The BAT ground-calculated position is RA, Dec = 272.172, -20.448 deg, which is RA(J2000) = 18h 08m 41.2s Dec(J2000) = -20d 26' 52.3" with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 98%. The mask-weighted light curve shows a single FRED-like pulse starting at ~T-0.05 sec, peaking at ~T+0.1 sec, with a long low-level tail out to T+0.5 or T+1.0 sec. T90 (15-350 keV) is 0.67 +- 0.16 sec (estimated error including systematics). There is no evidence of additional outbursts in the post 800 sec of the lightcurve at the 0.13 ph/cm2/sec upper limit. The time-averaged spectrum from T-0.05 to T+0.68 sec fit by a simple power-law model shows the power law index of 2.38 +- 0.42 (chi squared 69.8 for 57 d.o.f.). The fluence in the 15-150 keV band is 3.3 +- 0.8 x 10^-8 erg/cm2. The 1-sec peak photon flux measured from T-0.18 sec in the 15-150 keV band is 0.6 +- 0.1 ph/cm2/sec. A single blackbody fit to the time-averaged spectrum shows the blackbody temperature of 8.1 +- 2.1 keV (chi squared 71.9 for 59 d.o.f.). A thermal bremsstrahlung model fit shows the temperature of 38.3 +- 21.6 keV (chi squared 68.1 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/535747/BA/ /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14251 SUBJECT: Trigger 549841: Swift detection of SGR1806-20 DATE: 13/02/27 01:42:03 GMT FROM: David Palmer at LANL D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), C. Gronwall (PSU), J. A. Kennea (PSU), A. Y. Lien (NASA/GSFC/ORAU), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 01:21:40 UT, the Swift Burst Alert Telescope (BAT) triggered and located a burst from the known position of the Soft Gamma Repeater SGR 1806-20 (trigger=549841). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 272.183, -20.393 which is RA(J2000) = 18h 08m 44s Dec(J2000) = -20d 23' 33" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peak structure with a duration of about 0.128 sec. The peak count rate was ~5000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 01:22:31.6 UT, 50.8 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source with an enhanced position: RA, Dec 272.1635, -20.4104 which is equivalent to: RA(J2000) = 18h 08m 39.23s Dec(J2000) = -20d 24' 37.5" with an uncertainty of 3.1 arcseconds (radius, 90% containment). This location is 1.8 arcseconds from that of SGR 1806-20. UVOT took a finding chart exposure of 150 seconds with the White filter starting 53 seconds after the BAT trigger. No optical counterpart has been found in the initial data products. The 8'x8' region for the list of sources generated on-board covers SGR1806-20. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. BAT's most recent detection of a burst from this source was a month ago (2013-01-20), and a comparably-sized burst was most recently detected by BAT on 2010-03-26. /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14252 SUBJECT: SGR 1806-20 outburst (trigger 549841), Swift-BAT refined analysis DATE: 13/02/27 14:22:23 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) A. Y. Lien (NASA/GSFC/ORAU) (i.e. the Swift-BAT team): Using the data set from T-119 to T+183 sec from the recent telemetry downlink, we report further analysis of the outburst from SGR 1806-20 (trigger #549841) (Burrows, et al., GCN Circ. 14251). The BAT ground-calculated position is RA, Dec = 272.158, -20.399 deg which is RA(J2000) = 18h 08m 38.0s Dec(J2000) = -20d 23' 58.1" with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows a symmetrical peak with a total width of about 100 msec. T90 (15-350 keV) is 0.05 +- 0.01 sec (estimated error including systematics). There is no evidence of additional outbursts in the post 180 sec of the lightcurve at the 0.2 ph/cm2/sec 3-sigma upper limit. Several models are fit over a time-averaged spectrum from T-0.02 to T+0.04 sec. A simple power-law model shows the power law index of 2.43 +- 0.24 (chi squared 49.55 for 57 d.o.f.). The fluence in the 15-150 keV band is 2.1 +- 0.3 x 10^-8 erg/cm2. The 1-sec peak photon flux measured from T-0.49 sec in the 15-150 keV band is 0.5 +- 0.1 ph/cm2/sec. A single blackbody fit to the time-averaged spectrum shows the blackbody temperature of 8.24 +- 1.19 keV (chi squared 54.15 for 57 d.o.f.). A thermal bremsstrahlung model fit shows the temperature of 37.64 +- 11.54 keV (chi squared 45.71 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/549841/BA/ /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16183 SUBJECT: Trigger 597570: Swift detection of SGR 1806-20 DATE: 14/04/29 13:32:17 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), J. K. Cannizzo (NASA/UMBC), V. D'Elia (ASDC), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), M. H. Siegel (PSU) and E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift Team: At 13:13:28 UT, the Swift Burst Alert Telescope (BAT) triggered and located SGR 1806-20 (trigger=597570). Swift slewed immediately to the source. The BAT on-board calculated location is RA, Dec 272.159, -20.404 which is RA(J2000) = 18h 08m 38s Dec(J2000) = -20d 24' 12" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single spike with a duration of about 0.128sec. The peak count rate was ~11,000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 13:14:29.8 UT, 61.7 seconds after the BAT trigger. Using promptly downlinked data we find an X-ray source with an enhanced position: RA, Dec 272.1632, -20.4116 which is equivalent to: RA(J2000) = 18h 08m 39.16s Dec(J2000) = -20d 24' 41.7" with an uncertainty of 3.8 arcseconds (radius, 90% containment). This location is 30 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. This position is 3.1 arcsec from the known position of SGR 1806-20. No spectrum from the promptly downlinked event data is yet available to determine the column density. UVOT took a finding chart exposure of 150 seconds with the White filter starting 63 seconds after the BAT trigger. No credible optical counterpart has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. The last previous detection of this Soft Gamma Repeater by BAT was on April 5, 2014. /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16245 SUBJECT: Fermi GBM Trigger 140429551 - Detection of a burst from SGR 1806-20 DATE: 14/05/12 16:15:28 GMT FROM: Matthew Stanbro at UAH/Fermi SUBJECT: Fermi GBM Trigger 140429551 - Detection of a burst from SGR 1806-20 M. Stanbro (UAH) and G. Younes (USRA/MSFC) report on behalf of the Fermi GBM Team: "At 13:13:28.49 UT on 29 April 2014, the Fermi Gamma-Ray Burst Monitor triggered on a burst from SGR 1806-20, which was also detected by Swift/BAT (Barthelmy et. al. 2014, GCN 16183). The GBM on-ground location is consistent with the Swift position. The burst consists of a single pulse, with a duration of T90 = 0.13 +/- 0.02 s. The burst is well-fit with a power law function with an exponential high-energy cutoff parameterized as Epeak = 25 +/- 2 keV and an Index -0.3 +/- 0.5. The corresponding peak flux integrated over 4ms (8-200 keV) is (2.6 +/- 0.5)E-07 erg/s/cm^2. The fluence during T0-0.032s to T0+0.104s is (1.17 +/- 0.08)E-07 erg/cm^2. The analysis results presented above are preliminary." /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16632 SUBJECT: Trigger 607399: Swift detection of SGR1806-20 DATE: 14/07/29 02:51:50 GMT FROM: David Palmer at LANL M. G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB), C. B. Markwardt (NASA/GSFC), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 02:41:23 UT, the Swift Burst Alert Telescope (BAT) triggered and located a burst from the Soft Gamma Repeater SGR 1806-20 (trigger=607399). Swift slewed immediately to the burst location. The BAT on-board calculated location is RA, Dec 272.172, -20.437 which is RA(J2000) = 18h 08m 41s Dec(J2000) = -20d 26' 13" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty), which is 1.8 arcminutes from the location of the SGR. The BAT light curve showed a single-peaked structure with a duration of about 0.25 sec. The peak count rate was ~15000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 02:42:52.6 UT, 88.9 seconds after the BAT trigger. No source was detected in 303 s of promptly downlinked data. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 93 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17548 SUBJECT: Swift J0045.2+4151: analysis of XMM-Newton archival data DATE: 15/03/06 15:28:51 GMT FROM: Sandro Mereghetti at IASF/CNR A. Belfiore (INAF/IASF Milano), A. Tiengo (IUSS Pavia), G. L. Israel (INAF/OA Roma), A. M. Read (U. Leicester), R. Salvaterra, D. Salvetti (INAF/IASF Milano), G. Novara (IUSS Pavia), S. Mereghetti, M. Marelli (INAF/IASF Milano), G. Rodriguez (INAF/OA Roma), G. Lisini (IUSS Pavia), S. R. Rosen (U. Leicester), A. De Luca  (INAF/IASF Milano), report on behalf of the EXTraS collaboration: Based on the preliminary results of the EXTraS project (DeLuca et al. 2015, arXiv:1503.01497), we report on the analysis of XMM-Newton archival data of 3XMM J004514.7+415035 (aka [PFH2005] 622, Pietsch et al. 2005, ApJ 434, 483), the candidate X-ray counterpart of GRB 150301C  (aka Swift J0045.2+4151, GCN Circ 17512, 17516, 17536, 17544). The source is detected by the EPIC instrument at a 0.2-12 keV flux level of ~10^-14 erg/cm^2/s in two observations (2002-01-26 and 2007-01-05), while only upper limits of ~5x10^-14 erg/cm^2/s can be set from 5 shorter observations performed in July 2006. Shallow upper limits of ~10^-12 erg/cm^2/s can be derived from three non-detections during slew observations on 2005-07-03, 2007-01-06, and 2010-01-31. The EPIC light curves of the two observations show no evidence for variability. The search for coherent pulsations in the PN data, between 0.15 and 10^4 s, gives negative results. The blind search for transients does not report any significant candidates within the BAT error circle of GRB 150301C in any of the seven XMM-Newton observations. We extracted the EPIC spectra of 3XMM J004514.7+415035 and, after verifying that there are no significant spectral differences between the two observations, we fit them simultaneously with an absorbed power-law model. The best-fit parameters (errors at the 90% confidence level) are N_H<3x10^21 cm^-2 and photon index 1. 9 (-0.6, +0.8). Fixing the N_H to the Galactic value of 10^21 cm^-2, as appropriate for sources in the M31 disk, the photon index can be constrained in the 1.6-2.2 range (C-stat=142 for 143 degrees of freedom) and the unabsorbed flux in the 0.1-10 keV range is (1.3 +/- 0.3) x10^-14 erg/cm^2/s, corresponding to ~6x10^35 erg/s at the M31 distance. We note that the properties of 3XMM J004514.7+41503 are consistent with those of an active magnetar, like, e.g., SGR1806-20, at the distance of M31. Considering that the duration, fluence and spectrum of the burst detected by BAT are compatible with an intermediate flare from a magnetar in M31, 3XMM J004514.7+41503 might be considered as a magnetar candidate in the Andromeda galaxy. Plots of the long term flux evolution, the background-subtracted and exposure-corrected light curves, and the power density spectra with pulsed fraction upper limits can be found on the EXTraS website: http://www.extras-fp7.eu/index.php/home/90-extras/news/158-gcn-atel-1 EXTraS ("Exploring the X-ray Transient and variable Sky") is a project aimed at the systematic exploitation of the XMM/EPIC database, to search for, and characterize variability (both periodic and aperiodic), to search for new transients and to provide a phenomenological classification of variable sources. All EXTraS results, products and tools will be released to the community at the end of the project. EXTraS is carried out by a collaboration including INAF (Italy), IUSS (Italy), CNR/IMATI (Italy), University of Leicester (UK), MPE (Germany) and ECAP (Germany) and has been funded within the EU-FP7 framework (grant agreement n. 607452). /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19607 SUBJECT: SGR 1935+2154: AMI 15 GHz upper limits of the magnetar during outburst DATE: 16/06/28 12:55:20 GMT FROM: Kunal Mooley at Oxford U K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), T. Cantwell (Manchester), C. Rumsey, D. Titterington, S. H. Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), K. Grainge, A. Scaife (Manchester) We observed SGR 1935+2154 with the AMI Large Array at 15 GHz at several epochs, obtaining the following upper limits (3sigma). This magnetar has been in outburst since 14 May 2016, with 39 Fermi/GBM triggers (Younes et al., GCN 19598) and at least 7 Swift/BAT triggers (e.g. Barthelmy et al., GCN 19590). The AMI-LA robotically triggered on all the BAT alerts. The non-detections in the radio indicate that the magnetar outburst has not seen any giant flare similar to SGR 1806-20 in Dec 2004. --------------------- Date S (UT) (uJy) --------------------- 2016 May 16.98 <282 2016 May 18.21 <144 2016 May 20.22 <108 2016 May 21.27 <147 2016 May 22.07 <129 2016 May 23.12 <204 2016 May 27.17 <111 2016 Jun 25.05 <132 2016 Jun 26.97 <360 --------------------- We thank the AMI staff for scheduling these observations. /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23337 SUBJECT: Trigger 866993: Swift detection of SGR1806-20 DATE: 18/10/14 08:36:08 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), P. D'Avanzo (INAF-OAB) and A. Melandri (INAF-OAB) report on behalf of the Neil Gehrels Swift Observatory Team: At 08:15:34 UT, the Swift Burst Alert Telescope (BAT) triggered and located SGR1806-20 (trigger=866993). Swift did not slew to the source because of an observing constraint. The BAT on-board calculated location is RA, Dec 272.166, -20.380, which is RA(J2000) = 18h 08m 40s Dec(J2000) = -20d 22' 48" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single peak with a duration of about 3 sec. The peak count rate was ~2400 counts/sec (15-350 keV), at ~0 sec after the trigger. Due to a Moon observing constraint, Swift cannot slew to the BAT position until 2018 October 16. No XRT or UVOT follow-ups are planned. /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27672 SUBJECT: Trigger 968731: Swift detection of SGR1806-20 DATE: 20/04/30 13:10:14 GMT FROM: Scott Barthelmy at NASA/GSFC E. Ambrosi (INAF-IASFPA), S. D. Barthelmy (GSFC), V. D'Elia (SSDC), J.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC) and K. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift Observatory Team: At 12:56:41 UT, the Swift Burst Alert Telescope (BAT) triggered and located SGR1806-20 (trigger=968731). Swift did not slew to the source because the merit value has been set low on this source. The BAT on-board calculated location is RA, Dec 272.131, -20.398, which is RA(J2000) = 18h 08m 32s Dec(J2000) = -20d 23' 50" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single spike structure with a duration of about 0.2 sec. The peak count rate was ~3000 counts/sec (15-350 keV), at ~0 sec after the trigger. We plan shortly to execute a 2ks TOO observation with Swift in order to determine the flux state of this SGR. /////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27674 SUBJECT: Fermi GBM observation of a flare from the magnetar SGR 1806-20 DATE: 20/05/01 15:38:19 GMT FROM: Christian Malacaria at NASA-MSFC/USRA C. Malacaria (NASA/MSFC/USRA) reports on behalf of the Fermi GBM Team: "At 12:56:41 UT on 30 April 2020, the Swift Burst Alert Telescope (BAT) triggered and located SGR 1806-20 (GCN 27672). There was no Fermi-GBM onboard trigger around the event time. However, the GBM targeted search [1], the most sensitive, coherent search for sub-threshold signals, was run from +/-5 s around the trigger time, and identified a significant signal whose location is consistent with SGR 1806-20. The search was run down to a timescale of 4 ms and finds the most significant timescale at 32 ms, with a log likelihood ratio of 50. The flare spectrum is well fit by a blackbody model with a best-fit temperature value of kT=7.5+/-1.1 keV. The event fluence (8-100 keV) in this time interval is (1.5 +/- 0.3)E-7 erg/cm^2. The spectral analysis results presented above are preliminary. For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/ [1] Goldstein et al. 2019 arXiv:1903.12597" /////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33451 SUBJECT: Trigger 1159327: Swift detection of SGR1806-20 DATE: 23/03/10 21:15:35 GMT FROM: David Palmer at LANL R. Brivio (INAF-OAB), M. Ferro (INAF-OAB), D. M. Palmer (LANL), T. M. Parsotan (GSFC/UMBC/CRESSTII), C. Salvaggio (INAF-OAB), T. Sbarrato (INAF-OAB) and B. Sbarufatti (INAF-OAB) report on behalf of the Neil Gehrels Swift Observatory Team: At 21:00:35 UT, the Swift Burst Alert Telescope (BAT) triggered and located a bright burst from the Soft Gamma Repeater SGR 1806-20 (trigger=1159327). Swift did not immediately slew to the source. The BAT on-board calculated location is RA, Dec 272.154, -20.416 which is RA(J2000) = 18h 08m 37s Dec(J2000) = -20d 24' 56" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single spike structure with a duration of about 0.6 sec. The peak count rate was ~170,000 counts/sec (15-350 keV), at ~0 sec after the trigger. XRT follow-up observations are planned. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33473 SUBJECT: VZLUSAT-2 detection of SGR 1806-20 DATE: 23/03/13 21:28:20 GMT FROM: Marianna Dafcikova at Masaryk University <500025@mail.muni.cz> M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), H. Takahashi (Hiroshima U.), F. Munz , M. Topinka, F. Hroch, N. Husarikova, J.-P. Breuer (Masaryk U.), J. Hudec, J. Kapus, M. Frajt, M. Rezenov (Spacemanic s.r.o), R. Laszlo (Needronix), G. Galgoczi (Wigner Research Center/Eotvos U.), N. Uchida (ISAS/JAXA), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), Y. Fukazawa, K. Hirose, H. Matake (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), K. Torigoe (Hiroshima U.), P. Svoboda, V. Daniel, J. Dudas, M. Junas, J. Gromes (VZLU), I. Vertat (FEL ZCU) -- the VZLUSAT-2/GRB payload collaboration. The GRB detector on board the VZLUSAT-2 3U CubeSat ( https://www.vzlusat2.cz/en/) detected an outburst from the SGR 1806-20 (Swift/BAT detection: GCN 33451; Konus/Wind detection at 2023-03-10 21:00:32.718 UT; INTEGRAL/SPI-ACS detection at 2023-03-10 21:00:35 UT). The data acquisition was performed by GRB detector units no. 0 and no. 1. The detection was confirmed at the peak time 2023-03-10 21:00:34 UTC. The temporal resolution of the observation was 1 s and both light curves show a spike within one bin in the 40-110 keV band. The detection significance reached 8.6 sigma (19.4 sigma) for detector unit no. 0 (no. 1). The light curve obtained by VZLUSAT-2 is available here: https://vzlusat2.konkoly.hu/static/share/SGR1806-20_GCN_VZLUSAT2.pdf All VZLUSAT-2 detections are listed at: https://monoceros.physics.muni.cz/hea/VZLUSAT-2/ The GRB detectors on VZLUSAT-2 are a demonstration payload for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). Two GRB modules of VZLUSAT-2 are placed in a perpendicular manner and each consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~30 keV to ~1000 keV. VZLUSAT-2 was launched on 2022 January 13 from Cape Canaveral. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33495 SUBJECT: SGR 1806-20: Correction to GCN 33494 DATE: 23/03/21 10:26:59 GMT FROM: Sandro Mereghetti at IASF-Milano/INAF Sandro Mereghetti (INAF, IASF Milano) communicates: A mistake has been made in reporting the fluence of the SGR 1806-20 burst in GCN 33494. The correct value is 4e-8 erg/cm2 (20-200 keV). I apologize for the mistake. Note also that, due to a technical problem (which has now been fixed), the IBAS Alert corresponding to this trigger was not distributed in real time.