//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6411 SUBJECT: GRB 070517: Swift detection of a burst DATE: 07/05/17 11:40:57 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Vergani (DIAS-DCU), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), S. Campana (INAF-OAB), M. M. Chester (PSU), G. Cusumano (INAF-IASFPA), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA), W. B. Landsman (NASA/GSFC), V. Mangano (INAF-IASFPA), A. Moretti (INAF-OAB), P. T. O'Brien (U Leicester), J. P. Osborne (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), P. Romano (Univ. Bicocca & INAF-OAB), G. Sato (GSFC/ISAS), B. Sbarufatti (INAF-IASFPA), M. Stamatikos (NASA/ORAU), R. L. C. Starling (U Leicester), G. Tagliaferri (INAF-OAB), E. Troja (INAF-IASFPA) and H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team: At 11:20:58 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 070517 (trigger=279494). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 277.579, -62.333 which is RA(J2000) = 18h 30m 19s Dec(J2000) = -62d 19' 56" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows two peaks with a duration of about 10 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began taking data at 11:22:43 UT, 105 seconds after the BAT trigger. The XRT on-board centroid algorithm did not find a source in the image, but analysis of down-linked data yields a position: RA(J2000) = 18h 30m 29.4s Dec(J2000) = -62d 17' 50.8" with an uncertainty of 5.2 arcsec (radius, 90% containment). This position is 2.4 arcmin from the BAT position. The UVOT is unable to observe the field of GRB070517 due to the presence of a 4th magnitude star 8 arcmin from the burst's location. The Galactic reddening in the direction of the burst is E(B-V) = 0.15. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6412 SUBJECT: GRB 070517: Optical search DATE: 07/05/17 14:55:18 GMT FROM: Alan Gilmore at U of Canterbury,Mt John Obs A. C. Gilmore (Mt John Observatory of the University of Canterbury) reports: A total of 1200 seconds clear CCD exposures of the GRB 070517 region were taken with the 1-m f/7.7 reflector at Mt John Observatory in poor (3.5") seeing . The exposure set was centred on May 17 14:01 UT, 2.7 hours after the burst. No new object was seen to the limit of DSS-2 infrared in a 5' x 5' region approximately centred on the revised position of Vergani et al at (J2000) RA 18h 30m 30s Dec -62d 17' 50". //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6413 SUBJECT: GRB 070517, Swift-BAT refined analysis DATE: 07/05/17 20:06:54 GMT FROM: Hans Krimm at NASA-GSFC E. Fenimore (LANL), L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), S. D. Vergani (DIAS-DCU), on behalf of the Swift-BAT team: Using the data set from T-239.4 to T+302.8 sec from the recent telemetry downlink, we report further analysis of BAT GRB 070517 (trigger #279494) (Vergani, et al., GCN Circ. 6411). The BAT ground-calculated position is RA, Dec = 277.603, -62.297 deg which is RA(J2000) = 18h 30m 24.7s Dec(J2000) = -62d 17' 49.8" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 67%. The mask-weighted light curve shows a single peak lasting from approximately T+0 to T+10 seconds. T90 (15-350 keV) is 9.0 +- 1 sec (estimated error including systematics). The time-averaged spectrum from T-0.4 to T+10.6 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.81 +- 0.24. The fluence in the 15-150 keV band is 2.6 +- 0.4 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+1.65 sec in the 15-150 keV band is 0.8 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6414 SUBJECT: GRB070517: Swift-XRT Refined Analysis DATE: 07/05/17 23:42:11 GMT FROM: Susanna Vergani at INAF/Brera S.D. Vergani (DIAS-DCU) and P. Romano (INAF-OAB) report on behalf of the Swift Team: We have analysed the first four orbits of Swift XRT data from GRB070517 (trigger number 279494, GCN Circ. 6411) for a total of 8.9ks. The refined XRT position is RA/Dec(J2000) = 18h 30m 29.0s -62d 17' 51.7" which is RA/Dec(J2000) = 277.6207 -62.2977 with an uncertainty of 3.7 arcsec (radius, 90% containment). This position lies 3.5 arcsec from the XRT position and 2.4 arcmin from the BAT position given in GCN Circ. 6411 (Vergani et al.). The XRT PC light curve of the firts four orbits presents a flaring behaviour. A tentative fit with a power law gives a decay index alpha=0.4 +/- 0.1 The X-ray spectrum of the PC data can be fitted using an absorbed power law (photon index = 1.95 +/-0.07) with an absorbed column density fixed to the Galactic value (8.6e20 cm^-2; Dickey & Lockman, 1990). The absorbed (unabsorbed) 0.3-10.0keV flux for this spectrum was 1.9E-12 (2.3E-12) ergs cm^-2 s^-1. Assuming the source continues to decay at the same rate, we predict an XRT count rate of 1.8E-2 counts/s at T+24 hours, which corresponds to an observed flux of about 9E-13 ergs cm^-2 s^-1. This circular is an official product of the Swift XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6420 SUBJECT: GRB 070517: Gemini optical imaging DATE: 07/05/19 04:44:01 GMT FROM: Derek Fox at PSU D.B. Fox (Penn State), P.A. Price (Hawaii), and E. Berger (Carnegie Observatories) report: "We observed the refined XRT localization (Vergani & Romano, GCN 6414) of GRB 070517 (Vergani et al., GCN 6411) with the Gemini South telescope + GMOS-S, in a series of exposures beginning 03:23 UT on May 18, 2007. Within the refined XRT localization we identify a point-like source at coordinates R.A. 18:30:29.12, Dec -62:17:50.7 (uncertainty of <0.75" in each coordinate). This source is not present in DSS images of the region, although at an estimated brightness of r'=22.1 mag, i'=22.0 mag it lies beyond the depth of that survey. The source is detected in all of our imaged filters, g', r', i', and z'. We also identify a possible point-like source at coordinates R.A. 18:30:29.07, Dec -62:17:52.3 (uncertainty of <1.0" in each coordinate). This source is detected in the i' and z' bands only, with brightness i'~24.5 mag. Further observations will be necessary to assess the variable / afterglow nature of these sources."