//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19316 SUBJECT: GRB 160417A: Swift detection of a burst with an optical counterpart DATE: 16/04/17 04:34:46 GMT FROM: David Palmer at LANL P. D'Avanzo (INAF-OAB), A. Melandri (INAF-OAB), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 04:23:41 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 160417A (trigger=683076). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 120.240, +7.671 which is RA(J2000) = 08h 00m 58s Dec(J2000) = +07d 40' 15" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex peak structure with a duration of about 30 sec. The peak count rate was ~1100 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 04:25:53.1 UT, 132.2 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source located at RA, Dec 120.25774, 7.66265 which is equivalent to: RA(J2000) = 08h 01m 01.86s Dec(J2000) = +07d 39' 45.5" with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 70 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. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 2.92 x 10^20 cm^-2 (Willingale et al. 2013). UVOT took a finding chart exposure of 150 seconds with the White filter starting 135 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 08:01:01.64 = 120.25682 DEC(J2000) = +07:39:46.4 = 7.66290 with a 90%-confidence error radius of about 0.64 arc sec. This position is 4.4 arc sec. from the center of the XRT error circle. The estimated magnitude is 19.15 with a 1-sigma error of about 0.15. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02. Burst Advocate for this burst is P. D'Avanzo (paolo.davanzo AT brera.inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19317 SUBJECT: GRB 160417A: KAIT optical afterglow confirmation DATE: 16/04/17 05:00:15 GMT FROM: Weikang Zheng at UC Berkeley WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on behalf of the KAIT GRB team: The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, responded to Swift GRB 160417A (D'Avanzo et al., GCN 19316) about 10 minutes after the trigger. Observations were performed with an automatic sequence in the clear (roughly R), V, and I filters, and the exposure time was 20 s per image. Inside the XRT error circle we detected an un-cataloged source with coordinates of : RA = 08:01:01.64 (J2000) DEC= +07:39:46.60 (J2000) The object location is consistent with the position reported from UVOT (D'Avanzo et al., GCN 19316). The object has clear band mag of ~17.9 about 10 minutes after the burst. Follow-up observations are encouraged. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19318 SUBJECT: GRB 160417A: Enhanced Swift-XRT position DATE: 16/04/17 08:43:33 GMT FROM: Phil Evans at U of Leicester J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team. Using 1095 s of XRT Photon Counting mode data and 2 UVOT images for GRB 160417A, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 120.25686, +7.66288 which is equivalent to: RA (J2000): 08h 01m 1.65s Dec (J2000): +07d 39' 46.4" with an uncertainty of 1.8 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19319 SUBJECT: GRB 160417A: MITSuME Okayama upper limits DATE: 16/04/17 14:44:24 GMT FROM: Daisuke Kuroda at OAO/NAOJ D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ), S. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of MITSuME and OISTER collaboration: We observed the field of GRB 160417A (D'Avanzo et al., GCNC 19316) with the optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory. The observation started on 2016-04-17 11:06:00 UT (~6.7 h after the burst). We could not detect the previously reported afterglow (D'Avanzo et al., GCNC 19316; Zheng et al., GCNC 19317) in all the three bands. Three sigma upper limits of the OT are listed below. We used SDSS-DR8 catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' Rc Ic ----------------------------------------------------- 0.32136 12:06:26 5640.0 >19.7 >19.7 >18.9 ----------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19320 SUBJECT: GRB 160417A: Swift-XRT refined Analysis DATE: 16/04/17 15:47:59 GMT FROM: Phil Evans at U of Leicester A. D'Ai (INAF-IASFPA), A. Maselli (INAF-IASFPA), A. Melandri (INAF-OAB), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester) and P. D'Avanzo report on behalf of the Swift-XRT team: We have analysed 8.0 ks of XRT data for GRB 160417A (D'Avanzo et al. GCN Circ. 19316), from 117 s to 23.2 ks after the BAT trigger. The data comprise 41 s in Windowed Timing (WT) mode (the first 8 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN Circ. 19318). The light curve can be modelled with an initial power-law decay with an index of alpha=4.4 (+0.4, -0.3), followed by a break at T+305 s to an alpha of 0.59 (+/-0.06). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.05 (+0.15, -0.08). The best-fitting absorption column is consistent with the Galactic value of 2.9 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.1 x 10^-11 (3.4 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 2.9 (+/-1.9) x 10^20 cm^-2 Galactic foreground: 2.9 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 2.05 (+0.15, -0.08) If the light curve continues to decay with a power-law decay index of 0.59, the count rate at T+24 hours will be 0.013 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.9 x 10^-13 (4.3 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00683076. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19321 SUBJECT: GRB 160417A: iTelescope T11 optical observations DATE: 16/04/17 17:10:58 GMT FROM: Veli-Pekka Hentunen at Taurus Hill Obs,A95 Veli-Pekka Hentunen, Markku Nissinen and Tuomo Salmi (Taurus Hill Observatory, Varkaus, Finland) report: We have detected GRB 160417A optical afterglow at iTelescope observatory T11 (Mayhill, New Mexico) using 0.50-m f/6.8 astrograph and FLI PL11002M CCD. The observations were started at 2016-04-17 05:08:31 (UT). Two unfiltered images with 300 sec exposure time were taken. The afterglow was detected at the position RA 08:01:01.65 and DEC +07:39:47.6. The following magnitude was obtained from the observations using USNO-B1.0 0976-0191477 (R2=16.67) as a comparison star: Tmid(s)+T0 Filter Exp. time Mag Mag. Err. 2996 Clear 2x300s 18.6CR 0.3 --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19322 SUBJECT: GRB 160417A: Swift/UVOT Detection DATE: 16/04/17 18:40:24 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (UCL-MSSL) and P. D'Avanzo (INAF-OAB) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 160417A 136 s after the BAT trigger (D'Avanzo et al., GCN Circ. 19316). The source reported for the UVOT in the initial GCN and also by Zheng and Filippenko (GCN Circ. 19317) is found to be fading. The preliminary UVOT position is: RA (J2000) = 08:01:01.64 = 120.25685 (deg.) Dec (J2000) = +07:39:46.4 = 7.66289 (deg.) with an estimated uncertainty of 0.46 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 136 285 147 18.92 ± 0.07 white 870 1020 147 19.14 0.10 v 623 1070 58 18.54 ± 0.31 b 549 1169 58 19.07 ± 0.21 u 294 543 246 18.08 ± 0.08 w1 672 1280 64 >18.9 m2 647 1268 78 >19.1 w2 599 1220 78 >18.8 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19323 SUBJECT: GRB 160417A: Swift-BAT refined analysis DATE: 16/04/17 21:26:47 GMT FROM: Tilan Ukwatta at LANL S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), P. D'Avanzo (INAF-OAB), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 160417A (trigger #683076) (D'Avanzo, et al., GCN Circ. 19316). The BAT ground-calculated position is RA, Dec = 120.260, 7.646 deg which is RA(J2000) = 08h 01m 02.4s Dec(J2000) = +07d 38' 45.6" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 41%. The mask-weighted light curve shows a multi-peak episode starting ~T-4 sec, and ending around ~T+20 sec. T90 (15-350 keV) is 15 +- 2 sec (estimated error including systematics). The time-averaged spectrum from T-2.14 to T+13.89 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.93 +- 0.24. The fluence in the 15-150 keV band is 5.9 +- 0.8 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+1.51 sec in the 15-150 keV band is 1.0 +- 0.3 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/683076/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19324 SUBJECT: GRB 160417A: GMG observations DATE: 16/04/18 03:17:12 GMT FROM: Jirong Mao at Yunnan Obs J.-J. Zhang, J. Mao, and J.-M. Bai (YNAO) report: We observed the field of GRB 160417A (D'Avanzo et al., GCN 19316) with the 2.4-meter optical telescope at Gao-Mei-Gu (GMG) station of Yunnan Observatories. Observations began from 12:30:03 UT, Apr. 17th, 2016, about 8.2 hours after the trigger. We obtained the following results at the afterglow position: r~21.1+/- 0.3 mag, i>20.9 mag, and g>21.8 mag. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19384 SUBJECT: GRB 160417A, the review of the sky area in plate archive DATE: 16/05/04 20:55:29 GMT FROM: Valentyna Golovnya at Main Astro Obs,Kyiv V. V. Golovnia (Main Astro Obs., Kyiv) report: We have undertaken the review of the sky area of GRB 160417A (J.P. Osborne et al. GCN Circ. 19318) on astronegatives, collected in Ukrainian plate archive (1976-1996). All the plates with the possible object appearance are digitized using Epson Expression 10000XL flatbed scanner and the images have been placed into Golosiiv Plate Archive database DBGPA with open access to them. The list of plates is given in the table: yyyymmdd/TstartUT- ---Plates--- -Exp. Mag --USNO-A2-- 19930202/21:16:48 GUA040C002102 18.9 14.8 0975-05657018 19930216/20:33:08 GUA040C002131 19.5 16.0 0975-05654878 19930312/18:39:20 GUA040C002146 22.5 15.3 0975-05651231 Plates -the plates archive identifier of DWA D/F=400/2000, M=103"/mm (Marsden's number - 083) the plate number [1]. Exp. - Duration of the maximum exposures (minutes). Mag - Limited Bmag, derived in the 9 minutes area around the location given in J.P. Osborne et al.(GCN Circ. 19318): RA(J2000): 08h 01m 01.64s, Dec(J2000): +07d 39' 46.1". USNO-A2 - Comparison star. The preview images of 3 areas together with the 9 min. of arc area from Aladin can be found in http://gua.db.ukr-vo.org/img/grb/160417A/index.html. The images with full resolution are available via e-mail on demand. References: 1.L.Pakuliak DATABASE of GOLOSIIV PLATE ARCHIVE (DBGPA V2.0), http://gua.db.ukr-vo.org. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19509 SUBJECT: GRB 160417A: 15 GHz upper limits from AMI DATE: 16/06/08 15:16:24 GMT FROM: Kunal Mooley at Oxford U K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson (Curtin), T. Cantwell (Manchester), C. Rumsey, D. Titterington, S. Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), K. Grainge, A. Scaife (Manchester) The AMI Large Array robotically triggered on the Swift alert for GRB 160417A (D'Avanzo et al., GCN 19316) as part of the 4pisky program, and subsequent follow up observations were obtained up to 10 days post-burst. Our observations at 15 GHz on 2016 Apr 17.58, Apr 18.81, Apr 20.66, Apr 24.68, and Apr 28.77 (UT) do not reveal any radio source at the XRT location (Osborne et al., GCN 19318), with 3sigma upper limits of 225 uJy, 105 uJy, 123 uJy, 72 uJy, and 96 uJy respectively. We thank the AMI staff for scheduling these observations. The AMI-GRB database is a log of all GRB follow up observations with the AMI, and is available at http://4pisky.org/ami-grb/.