GRB050826: Swift-BAT detection of a long burst

TITLE: GCN GRB OBSERVATION REPORT
NUMBER: 3884
SUBJECT: GRB050826: Swift-BAT detection of a long burst
DATE: 05/08/26 07:02:02 GMT
FROM: Craig Markwardt at NASA/GSFC/UMD Scott@lheamail.gsfc.nasa.gov

V. Mangano (INAF-IASF), L. Barbier (GSFC), A. Blustin (UCL-MSSL), D. Burrows (PSU), J. Cummings (GSFC), S. Hunsberger (PSU), C. Markwardt (GSFC/UMD), D. Morris (PSU), K. Page (U. Leicester), D. Palmer (LANL), on behalf of the Swift team:

At 06:18:10 UT, Swift-BAT triggered and located GRB 050826 (trigger=152113). The spacecraft slewed immediately. The BAT on-board calculated location is RA,Dec 87.729, -2.680 {+05h 50m 55s, -02d 40′ 46″} (J2000), with an uncertainty of 3 arcmin (radius, 90% containment, stat+sys). The BAT light curve shows two peaks (T+10 sec and T+30 sec) with a total duration of 45 sec. The peak count rate was ~800 counts/sec (15-350 keV), at ~10 sec after the trigger.

Observations by the Swift X-Ray Telescope (XRT) began at 06:19:56 UT (106 seconds after the BAT trigger) with the XRT in the auto state. The on-board detection algorithm failed to find a centroid, suggesting a very faint source. More information will be available around 11:00 UT, after the next Malindi pass.

The UVOT began observing the field of GRB 050826 at 06:19:55 UT, 105 s after the BAT trigger. The UVOT image covers the whole of the 3 arcmin BAT error circle. A comparison of the parameterised UVOT finding chart, based on a 100 sec V-band image, with the DSS image reveals no new source brighter than ~19th mag.