TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5292 SUBJECT: GRB 060708: Swift detection of a burst with an UVOT countpart DATE: 06/07/08 12:34:38 GMT FROM: Scott Barthelmy at NASA/GSFC A. Moretti (INAF-OAB), L. M. Barbier (NASA/GSFC), S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), C. B. Markwardt (GSFC/UMD), K. M. McLean (LANL/UTD), D. M. Palmer (LANL), A. M. Parsons (GSFC), P. Romano (INAF-OAB) and D. E. Vanden Berk (PSU) report on behalf of the Swift Team: At 12:15:59 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 060708 (trigger=217805). Swift slewed immediately to the burst. The BAT on-board calculated location is RA,Dec 7.798, -33.730 {00h 31m 12s, -33d 43' 46"} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single, roughly triangular peak structure with a duration of ~12 sec. The peak count rate was ~5000 counts/sec (15-350 keV), at ~2 sec after the trigger. The XRT began observing the field at 12:17:01 UT, 62 seconds after the BAT trigger. XRT found a bright and fading X-ray source located at RA(J2000) = 00 31 13.50, Dec(J2000) = -33 45 33.8, with an estimated uncertainty of 4.1 arcseconds (90% confidence radius). This location is 103 arcseconds from the BAT on-board position, within the BAT error circle and it is 4.6" from the UVOT candidate (see below). The initial flux in the 2.5s image was 3.4e-09 erg/cm2/s (0.2-10 keV). UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 72 seconds after the BAT trigger. There is a candidate afterglow in the list of sources generated on-board at (RA,DEC) (J2000) of (7.8077,-33.7590) or (00h31m13.85s,-33o45'32.4") with a 1-sigma error radius of about 0.5 arcsec. This position is 4.5 arcsec from the center of the XRT error circle. The estimated magnitude is 17.4 with a 1-sigma error of about 0.5 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.01.