TITLE: GCN CIRCULAR NUMBER: 5795 SUBJECT: GRB 061110: Swift detection of a burst DATE: 06/11/10 12:22:08 GMT FROM: Scott Barthelmy at NASA/GSFC A. D. Falcone (PSU), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), S. Campana (INAF-OAB), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), V. Mangano (INAF-IASFPA), F. E. Marshall (NASA/GSFC), T. Mineo (INAF-IASFPA), C. Pagani (PSU), D. M. Palmer (LANL), M. Perri (ASDC), P. Romano (Univ. Bicocca & INAF-OAB), G. Sato (GSFC/ISAS) and L. Vetere (PSU) report on behalf of the Swift Team: At 11:47:21 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 061110 (trigger=238108). Swift slewed immediately to the burst. The BAT on-board calculated location is RA,Dec 336.304, -2.267 {22h 25m 13s, -02d 16' 00"} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows multiple peaks with a duration of about 30 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~5 sec after the trigger. The XRT began observing the field at 11:48:30 UT, 69 seconds after the BAT trigger. XRT found a bright, fading, uncatalogued X-ray source on-board. The ground-calculated position, based on quick-look data products, is RA(J2000) = 22h 25m 10.0s, Dec(J2000) = -02d 15' 29.1", with an estimated uncertainty of 4.3 arcseconds (90% confidence radius). This location is 55.8 arcseconds from the BAT on-board position, within the BAT error circle. The initial flux in the 2.5s image was 5.2e-09 erg/cm2/s (0.2-10 keV). UVOT took a finding chart exposure of 400 seconds with the V filter starting 71 seconds after the BAT trigger. No 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 3-sigma upper limit is 19.0 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 18.0 mag. No correction has been made for the expected extinction of about 0.3 magnitudes. We note that there are at least 35 galaxies within 10 arcmin of the burst position.