//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20023 SUBJECT: GRB 161011A: Swift detection of a burst DATE: 16/10/11 06:07:15 GMT FROM: David Palmer at LANL V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Y. Lien (GSFC/UMBC), K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 05:54:54 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 161011A (trigger=716876). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 245.710, +8.326 which is RA(J2000) = 16h 22m 51s Dec(J2000) = +08d 19' 34" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 5 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 05:56:44.4 UT, 110.4 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source located at RA, Dec 245.72866, 8.31221 which is equivalent to: RA(J2000) = 16h 22m 54.88s Dec(J2000) = +08d 18' 44.0" with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 82 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 5.25 x 10^20 cm^-2 (Willingale et al. 2013). The initial flux in the 2.5 s image was 5.16e-10 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 117 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 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 expected extinction corresponding to E(B-V) of 0.07. Burst Advocate for this burst is V. D'Elia (delia AT asdc.asi.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: 20024 SUBJECT: GRB 161011A: Prompt enhanced Swift-XRT position DATE: 16/10/11 06:26:50 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Using promptly downlinked XRT event data for GRB 161011A, we find an enhanced XRT position of the afterglow: RA, Dec: 245.7285, 8.3113 which is equivalent to: RA (J2000) = 16 22 54.85 Dec (J2000) = +08 18 40.6 with an uncertainty of 2.2 arcseconds (radius, 90% confidence). Analysis of the promptly available data is online at http://www.swift.ac.uk/sper/716876. Position enhancement is is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20026 SUBJECT: GRB 161011A: Enhanced Swift-XRT position DATE: 16/10/11 12:11:54 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 985 s of XRT Photon Counting mode data and 2 UVOT images for GRB 161011A, 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 = 245.72859, +8.31105 which is equivalent to: RA (J2000): 16h 22m 54.86s Dec (J2000): +08d 18' 39.8" with an uncertainty of 1.9 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: 20028 SUBJECT: GRB 161011A: Swift-XRT refined Analysis DATE: 16/10/11 16:05:58 GMT FROM: Phil Evans at U of Leicester J.A. Kennea (PSU), K.L. Page (U. Leicester), B. Mingo (U. Leicester), A.P. Beardmore (U. Leicester), P. D'Avanzo (INAF-OAB), A. D'Ai (INAF-IASFPA), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU) and V. D'Elia report on behalf of the Swift-XRT team: We have analysed 6.3 ks of XRT data for GRB 161011A (D'Elia et al. GCN Circ. 20023), from 100 s to 23.1 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. 20024). The light curve can be modelled with an initial power-law decay with an index of alpha=3.77 (+0.19, -0.17), followed by a break at T+443 s to an alpha of 0.06 (+0.08, -0.09). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.75 (+0.18, -0.17). The best-fitting absorption column is 7.8 (+5.1, -2.6) x 10^20 cm^-2, consistent with the Galactic value of 5.3 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 3.8 x 10^-11 (4.3 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 7.8 (+5.1, -2.6) x 10^20 cm^-2 Galactic foreground: 5.3 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 1.75 (+0.18, -0.17) If the light curve continues to decay with a power-law decay index of 0.06, the count rate at T+24 hours will be 0.072 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.7 x 10^-12 (3.1 x 10^-12) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00716876. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20029 SUBJECT: GRB 161011A: Swift/UVOT Upper Limits DATE: 16/10/11 17:23:48 GMT FROM: Frank Marshall at GSFC F. E. Marshall (NASA/GSFC) and V. D'Elia (ASDC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 161011A 118 s after the BAT trigger (D'Elia et al., GCN Circ. 20023). No optical afterglow consistent with the XRT position (Osborne et al., GCN Circ. 20026) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 118 268 147 >20.7 u_FC 330 580 246 >20.0 white 118 1009 334 >21.1 v 660 6564 255 >19.4 b 586 11301 252 >20.3 u 330 11089 1170 >20.6 w1 709 6889 152 >20.4 m2 6569 6769 197 >20.3 w2 1015 6359 216 >20.0 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.07 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20030 SUBJECT: GRB 161011A: TSHAO afterglow candidate DATE: 16/10/11 22:10:02 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), A. Kusakin (Fesenkov Astrophysical Institute), A. Volnova (IKI), I. Reva (Fesenkov Astrophysical Institute), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of GRB 161011A (D'Elia et al., GCN 20023) with Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical Observatory. We obtained several images in R filter starting on Oct. 11 (UT) 13:13:27. In the enhanced XRT error circle (Osborne al., GCN 20026) we marginally detect an object which is absent in SDDS-DR9 catalog. Preliminary photometry of the object which we suggest as an afterglow candidate is following Date UT start t-T0 Filter Exp. OT Err. UL (mid, days) (s) 2016-10-11 13:13:27 0.32098 R 21*120 20.6 0.3 20.8 Photometry is based on nearby SDSS-DR9 stars (Lupton transformations): SDSS-DR9_id R J162253.68+081834.3 15.26 J162242.22+082241.1 14.18 J162312.65+081527.2 14.72 J162302.30+081614.7 14.96 A finding chart can be found at http://grb.rssi.ru/GRB161011A/GRB161011A_TSHAO_161011_fc.png //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20031 SUBJECT: GRB 161011A: Swift burst of interest DATE: 16/10/11 22:22:59 GMT FROM: Massimiliano de Pasquale at IASF-Palermo M. De Pasquale (MSSL-UCL), N. Gehrels (GSFC), J. Kennea (PSU). The light-curve of Swift GRB 161011A X-ray afterglow shows strong variability around a flux level of a few 10^{-12} / erg cm^2 s. The Swift team decleares this GRB a "burst of interest". We encourage ground based follow up observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20032 SUBJECT: GRB 161011A, Swift-BAT refined analysis DATE: 16/10/12 03:08:56 GMT FROM: Amy Lien at GSFC T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), V. D'Elia (ASDC), 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), (i.e. the Swift-BAT team): Using the data set from T-790 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 161011A (trigger #716876) (D'Elia, et al. GCN Circ. 20023). The BAT ground-calculated position is RA, Dec = 245.687, 8.313 deg which is RA(J2000) = 16h 22m 44.9s Dec(J2000) = +08d 18' 47.3" with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 43%. The mask-weighted light curve shows a weak single-pulse structure that starts at ~T0, peaks at ~ T+1 s, and ends at ~T+5 s. T90 (15-350 keV) is 4.3 +- 1.3 sec (estimated error including systematics). The time-averaged spectrum from T-0.3 to T+4.4 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.15 +- 0.35. The fluence in the 15-150 keV band is 2.3 +- 0.4 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+1.37 sec in the 15-150 keV band is 0.9 +- 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/716876/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20041 SUBJECT: GRB 161011A: RATIR Optical and NIR Observations DATE: 16/10/14 19:25:39 GMT FROM: Eleonora Troja at GSFC Eleonora Troja (GSFC), Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), José A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report: We observed the field of GRB 161011A (D'Elia, et al., GCN 20023) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir from 2016/10 13.11 to 2016/10 13.15 UTC (44.66 to 45.69 hours after the BAT trigger), obtaining a total of 0.69 hours exposure in the r and i bands and 0.27 hours exposure in the Z, Y, J, and H bands. We do not detect the optical source reported by Mazaeva, et al. (GCN 20030). For a source within the Swift-XRT error circle (Osborne, et al., GCN 20026), in comparison with the SDSS DR9 and 2MASS catalogs, we obtain the following detections and upper limits (3-sigma): r > 23.4 i > 22.7 Z > 21.7 Y > 21.4 J > 21.0 H > 20.7 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20084 SUBJECT: GRB 161011A: 15 GHz upper limits from AMI DATE: 16/10/20 10:38:44 GMT FROM: Kunal Mooley at Oxford U K. P. Mooley (Hintze Fellow, Oxford), T. D. Staley, R. P. Fender (Oxford), G. E. Anderson (Curtin), T. Cantwell (Manchester), D. Titterington, S. H. 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 the burst of interest GRB 161011A (D'Elia et al., GCN 20023; Pasquale et al., GCN 20031) 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 Oct 11.44, Oct 13.66, Oct 14.60 and Oct 18.56 (UT) do not reveal any radio source at the XRT location (Osborne et al., GCN 20026), with 3sigma upper limits of 171 uJy, 117 uJy, 108 uJy and 147 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/. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20105 SUBJECT: Radio upper limit on the GRB 161011A with the GMRT DATE: 16/10/24 07:00:22 GMT FROM: Nayana A J at NCRA-TIFR A. J. Nayana (NCRA-TIFR), Vikas Chand (TIFR), Poonam Chandra (NCRA-TIFR) and A.R. Rao (TIFR) report: We carried out the Giant Metrewave Radio Telescope (GMRT) observations of GRB 161011A (GCN Circ 20023) in the 1390 MHz band on 2016 October 21.71 UT. We do not detect radio afterglow of the GRB in this frequency band. The 3-sigma upper limit at the GRB position (GCN Circ. 20026) is 120 uJy. We thank GMRT staff for making these observations possible.