TITLE: GCN CIRCULAR NUMBER: 7920 SUBJECT: GRB 080702: Swift detection of a short burst DATE: 08/07/02 12:10:31 GMT FROM: David Palmer at LANL M. De Pasquale (UCL-MSSL), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), C. Guidorzi (INAF-OAB), J. A. Kennea (PSU), V. Mangano (INAF-IASFPA), F. E. Marshall (NASA/GSFC), C. Pagani (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL), P. Romano (INAF-IASFPA), T. Sakamoto (NASA/UMBC), B. Sbarufatti (INAF-IASFPA), P. Schady (MSSL-UCL), M. Stamatikos (NASA/ORAU), E. Troja (INAF-IASFPA), T. N. Ukwatta (GSFC/GWU) and P. A. Ward (MSSL-UCL) report on behalf of the Swift Team: At 11:50:43 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 080702 (trigger=315710). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 312.853, +72.308 which is RA(J2000) = 20h 51m 25s Dec(J2000) = +72d 18' 28" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a double-peaked structure with the second peak larger and a total duration of about 1.5 sec. The peak count rate was ~3000 counts/sec (15-350 keV), at ~0.5 sec after the trigger, during the second peak. The XRT began observing the field at 11:51:50.0 UT, 66.3 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source with an enhanced position: RA, Dec 313.05101, 72.31271 which is equivalent to: RA(J2000) = 20h 52m 12.24s Dec(J2000) = +72d 18' 45.8" with an uncertainty of 3.0 arcseconds (radius, 90% containment). This location is 217 arcseconds from the BAT onboard position, slightly outside the BAT error circle. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 1.53e+21 cm^-2 (Kalberla et al. 2005). UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 72 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The XRT position is outside the 2.7'x2.7' sub-image. 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 0.67. Burst Advocate for this burst is M. De Pasquale (mdp AT mssl.ucl.ac.uk). 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.)