TITLE: GCN CIRCULAR NUMBER: 9325 SUBJECT: GRB 090509: Swift detection of a burst DATE: 09/05/09 05:21:22 GMT FROM: Scott Barthelmy at NASA/GSFC D. Grupe (PSU), S. D. Barthelmy (GSFC), M. M. Chester (PSU), H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), J. L. Racusin (PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 05:10:03 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 090509 (trigger=351525). Swift did not slew to this burst. The BAT on-board calculated location is RA, Dec 241.404, -28.404 which is RA(J2000) = 16h 05m 37s Dec(J2000) = -28d 24' 12" 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 ~1300 counts/sec (15-350 keV), at ~20 sec after the trigger. Due to the Moon observing constraint, Swift cannot slew to the BAT position until May 12. There will thus be no XRT or UVOT data for this trigger. Burst Advocate for this burst is D. Grupe (grupe AT astro.psu.edu). 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.)