TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5285 SUBJECT: GRB 060707: Swift detection of a burst DATE: 06/07/07 22:00:53 GMT FROM: Scott Barthelmy at NASA/GSFC A. Moretti (INAF-OAB), S. D. Barthelmy (GSFC), P. T. Boyd (NASA/GSFC), P. J. Brown (PSU), M. M. Chester (PSU), N. Gehrels (NASA/GSFC), C. Guidorzi (Univ Bicocca&INAF-OAB), J. A. Kennea (PSU), C. B. Markwardt (GSFC/UMD), F. E. Marshall (NASA/GSFC), K. M. McLean (LANL/UTD), C. Pagani (PSU), D. M. Palmer (LANL), T. Sakamoto (NASA/ORAU), M. Stamatikos (NASA/ORAU) and D. E. Vanden Berk (PSU) report on behalf of the Swift Team: At 21:30:19 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 060707 (trigger=217704). Swift slewed immediately to the burst. The BAT on-board calculated location is RA,Dec 357.079, -17.923 {23h 48m 19s, -17d 55' 21"} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single FRED-like peak at T_0 lasting about 30 sec. There is a hard precusor at T-45 sec. The total duration is ~75 sec. The peak count rate was ~1500 counts/sec (15-350 keV), at ~2 sec after the trigger. The XRT began taking data at 21:32:20 UT, 122 seconds after the BAT trigger. The XRT on-board centroid algorithm did not find a source in the image and no prompt position is available. Down-linked data show a bright source at RA(2000)=23 48 19.00 DEC(2000):-17 54 21.8 with an error circle of 3.8". This position is 60" from the BAT position. UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 126 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle and 100% of the ground-determined XRT error circle. The typical 3-sigma upper limit has been about 18.5 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT 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 0.02.