TITLE: GCN CIRCULAR NUMBER: 15069 SUBJECT: Trigger 565443: Swift detection of a burst from SGR J1745-29 DATE: 13/08/05 02:43:52 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), V. Mangano (PSU), C. J. Mountford (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 02:09:09 UT, the Swift Burst Alert Telescope (BAT) triggered and located a burst consistent with the location of the Soft Gamma Repeater SGR J1745-29. Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 266.420, -29.004 which is RA(J2000) = 17h 45m 41s Dec(J2000) = -29d 00' 14" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single short soft peak with a duration of 64 ms. The peak count rate was ~4000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 02:10:11.0 UT, 61.2 seconds after the BAT trigger. Using promptly downlinked data we detect several x-ray sources as expected for the Galactic Center region. Further analysis using the full data will be required to identify the source of this event. UVOT took a finding chart exposure of 150 seconds with the White filter starting 66 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. 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 large, but uncertain extinction expected. We believe that this is further activity from the SGR J1745-29 source which BAT last detected on June 7 of this year. (The Chandra location of this source is given in ATEL #5032.)