//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19657 SUBJECT: GRB 160705B: Swift detection of a burst DATE: 16/07/05 21:19:59 GMT FROM: Scott Barthelmy at NASA/GSFC J. K. Cannizzo (NASA/UMBC), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), C. Gronwall (PSU), J. A. Kennea (PSU), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester) and T. N. Ukwatta (LANL) report on behalf of the Swift Team: At 21:02:07 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 160705B (trigger=703176). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 168.086, +46.721 which is RA(J2000) = 11h 12m 21s Dec(J2000) = +46d 43' 17" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows some weak emission from T_0 to about T+40 (this is a 64-sec image trigger, and as such there is seldom anything see in the raw real-time TDRSS telemetry). The duration of about 40 sec. The peak count rate was ~600 counts/sec (15-350 keV), at ~3 sec after the trigger. The XRT began observing the field at 21:04:27.7 UT, 140.3 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source located at RA, Dec 168.10943, 46.70085 which is equivalent to: RA(J2000) = 11h 12m 26.26s Dec(J2000) = +46d 42' 03.1" with an uncertainty of 3.6 arcseconds (radius, 90% containment). This location is 92 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 in excess of the Galactic value (1.19 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 2.7 (+2.18/-1.93) x 10^21 cm^-2 (90% confidence). The initial flux in the 2.5 s image was 9.31e-10 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 148 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 0.01. Burst Advocate for this burst is J. K. Cannizzo (cannizzo AT milkyway.gsfc.nasa.gov). 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: 19658 SUBJECT: GRB 160705B: LT optical candidate DATE: 16/07/05 22:14:16 GMT FROM: Cristiano Guidorzi at Ferrara U,Italy C. Guidorzi (U. Ferrara), C.G. Mundell (U. Bath), S. Kobayashi, I.A. Steele (LJMU), A. Gomboc (U. Nova Gorica) on behalf of a large collaboration report: The 2-m Liverpool Telescope began observing Swift GRB 160705B (Cannizzo et al., GCN 19657) on July 05, 21:05:14 UT (3.1 minutes after the burst trigger). Inside the XRT error circle we find an uncatalogued source which is not present in the SDSS at the following position: RA(J2000)= 11:12:26.27 Dec(J2000)= +46:42:01.2 with an uncertainty of 0.5 arcsec and r~21 mag (AB) @ 36 minutes post GRB. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19659 SUBJECT: GRB 160705B: Enhanced Swift-XRT position DATE: 16/07/06 05:45:04 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 2204 s of XRT Photon Counting mode data and 3 UVOT images for GRB 160705B, 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 = 168.10944, +46.69990 which is equivalent to: RA (J2000): 11h 12m 26.27s Dec (J2000): +46d 41' 59.6" with an uncertainty of 1.6 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: 19660 SUBJECT: GRB 160705B: Swift-XRT refined Analysis DATE: 16/07/06 06:46:50 GMT FROM: Phil Evans at U of Leicester D.N. Burrows (PSU), T.G.R. Roegiers (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), S.L. Gibson (U. Leicester), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), L.M. McCauley (PSU) and J.K. Cannizzo report on behalf of the Swift-XRT team: We have analysed 6.3 ks of XRT data for GRB 160705B (Cannizzo et al. GCN Circ. 19657), from 130 s to 23.8 ks after the BAT trigger. The data comprise 132 s in Windowed Timing (WT) mode (the first 9 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. 19659). The light curve can be modelled with an initial power-law decay with an index of alpha=3.81 (+0.14, -0.13), followed by a break at T+563 s to an alpha of 0.60 (+0.12, -0.13). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.66 (+0.14, -0.13). The best-fitting absorption column is 10.0 (+2.5, -2.4) x 10^20 cm^-2, in excess of the Galactic value of 1.2 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 2.15 (+0.23, -0.21) and a best-fitting absorption column of 8.1 (+5.2, -4.5) x 10^20 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.1 x 10^-11 (3.8 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 8.1 (+5.2, -4.5) x 10^20 cm^-2 Galactic foreground: 1.2 x 10^20 cm^-2 Excess significance: 2.5 sigma Photon index: 2.15 (+0.23, -0.21) If the light curve continues to decay with a power-law decay index of 0.60, the count rate at T+24 hours will be 0.012 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.5 x 10^-13 (4.4 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/00703176. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19662 SUBJECT: GRB 160705B: Swift-BAT refined analysis DATE: 16/07/06 11:37:09 GMT FROM: Scott Barthelmy at NASA/GSFC C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), J. K. Cannizzo (NASA/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), 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 downlinks, we report further analysis of BAT GRB 160705B (trigger #703176) (Cannizzo, et al., GCN Circ. 19657). The BAT ground-calculated position is RA, Dec = 168.107, 46.707 deg, which is RA(J2000) = 11h 12m 25.7s Dec(J2000) = +46d 42' 24.8" with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 73%. The mask-weighted light curve shows possible emission from before T-239 sec (the beginning of the data), with the peak starting at ~T-30 sec, peaking at ~T+10 sec, and ending at ~T+90 sec. T90 (15-350 keV) is 54.4 +- 12.4 sec (estimated error including systematics). The time-averaged spectrum from T-15.09 to T+54.70 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.79 +- 0.27. The fluence in the 15-150 keV band is 7.3 +- 1.1 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+26.04 sec in the 15-150 keV band is 0.5 +- 0.2 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/703176/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19663 SUBJECT: GRB 160705B: RATIR Optical and NIR Observations and Confirmation of the Fading Afterglow DATE: 16/07/06 13:50:49 GMT FROM: Alan M. Watson at Instituto de Astronomia UNAM Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (GSFC/STScI), Eleonora Troja (GSFC), 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 160705B (Cannizzo et al., GCN 19657) 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 2016/07 6.17 to 2016/07 6.21 UTC (7.04 to 8.05 hours after the BAT trigger), obtaining a total of 0.66 hours exposure in the r and i bands and 0.30 hours exposure in the Z, Y, J, and H bands. We detect two sources within the enhanced Swift-XRT error circle (Osborne et al., GCN 19659). The brighter source is an uncataloged source at 11:12:26.20 +46:42:01.2 (J2000, +/- 0.5 arcsec) with the following detections and 3-sigma upper limit: r = 22.89 +/- 0.15 i = 22.12 +/- 0.09 Z = 22.34 +/- 0.33 Y = 21.73 +/- 0.32 J > 21.54 H = 20.98 +/- 0.34 The fainter source is a cataloged SDSS source at 11:12:26.42 +46:41:59.6 (J2000, +/- 0.5 arcsec) with the following detections and 3-sigma upper limits: r = 23.39 +/- 0.24 i = 22.61 +/- 0.14 Z = 22.10 +/- 0.26 Y > 21.87 J > 21.54 H > 21.04 These magnitudes are in the AB system, are in comparison with the SDSS DR9 and 2MASS catalogs, and are not corrected for Galactic extinction in the direction of the GRB. We note that Guidorzi et al. (GCN 19658) report an uncataloged source with r of about 21 at 36 minutes after the burst trigger. Their source is only 0.7 arcsec from our brighter uncataloged source and so we postulate that these correspond to the afterglow of the GRB. The afterglow has faded by about 2 magnitudes between their observations at 36 minutes and ours at 7.54 hours, which corresponds to a temporal index of about -0.6. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19664 SUBJECT: GRB 160705B: Swift/UVOT Upper Limits DATE: 16/07/06 20:47:42 GMT FROM: Sam Emery at MSSL-UCL S.W.K. Emery (UCL-MSSL) and J. K. Cannizzo (NASA/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 160705B 149 s after the BAT trigger (Cannizzo et al., GCN Circ. 19657). No optical afterglow consistent with the XRT position (Osborne et al. GCN Circ. 19659) or the LT and RATIR position (Guidorzi et al. GCN 19658; Watson et al. GCN Circ. 19663) 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 149 298 147 >20.6 u_FC 307 557 246 >19.9 white 4780 6415 393 >21.0 v 5191 11327 1082 >19.9 b 6011 6210 197 >20.1 w1 12239 12529 285 >20.0 m2 11333 12232 886 >20.7 w2 6421 6603 179 >19.9 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19672 SUBJECT: GRB 160705B: TAROT Calern observatory optical observations DATE: 16/07/09 23:17:47 GMT FROM: Alain Klotz at IRAP-CNRS-OMP Klotz A., Turpin D., Atteia J.L. (CNRS-OMP-IRAP), Boer, M., Laugier, R. (CNRS-ARTEMIS), Gendre B. (UVI - Etelman Obs.) report: We imaged the field of GRB 160705B detected by SWIFT (trigger 703176) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. The observations started 92s after the GRB trigger (18s after the notice). The elevation of the field decreased from 36 degrees above horizon and weather conditions were poor. The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). We do not detect any OT with a limiting magnitude of: t0+92s to t0+152s : Rlim = 15.5 The second image is 30.0s exposure in tracking mode: t0+190s to t0+250s : Rlim = 16.6 Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19738 SUBJECT: GRB 160705B: 15 GHz upper limits from AMI DATE: 16/07/28 17:40:39 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. 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 GRB 160705B (Cannizzo et al., GCN 19657) 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 Jul 05.89, Jul 06.73, Jul 08.74, and Jul 12.72 (UT) do not reveal any radio source at the XRT location (Osborne et al., GCN 19659), with 3sigma upper limits of 177 uJy, 102 uJy, 132 uJy, and 213 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/.