TITLE: GCN CIRCULAR NUMBER: 8782 SUBJECT: GRB 090107: Swift detection of a burst DATE: 09/01/07 05:00:06 GMT FROM: David Palmer at LANL T. N. Ukwatta (GSFC/GWU), J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), W.B Landsman (GSFC), D. M. Palmer (LANL), M. Perri (ASDC) and G. Stratta (ASDC) report on behalf of the Swift Team: At 04:48:04 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 090107 (trigger=339295). Swift could not slew to this burst due to its proximity to the Sun. The BAT on-board calculated location is RA, Dec 302.426, +4.727 which is RA(J2000) = 20h 09m 42s Dec(J2000) = +04d 43' 39" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a double-peaked structure with a duration of about 25 sec, with a possible additional peak at T+75 sec. The peak count rate was ~2000 counts/sec (15-350 keV), at ~0 sec after the trigger. Due to the Sun observing constraint, Swift cannot slew to the BAT position. There will thus be no XRT or UVOT data for this trigger. Burst Advocate for this burst is T. N. Ukwatta (tilan.ukwatta AT gmail.com). 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.)