TITLE: GCN CIRCULAR NUMBER: 17434 SUBJECT: GRB 150211A: Swift detection of a burst DATE: 15/02/11 12:09:47 GMT FROM: Scott Barthelmy at NASA/GSFC R. L. C. Starling (U Leicester), S. D. Barthelmy (GSFC), M. M. Chester (PSU), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU) and K. L. Page (U Leicester) report on behalf of the Swift Team: At 11:52:11 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150211A (trigger=630714). Swift did not slew because of observing constraint. The BAT on-board calculated location is RA, Dec 254.856, +55.383, which is RA(J2000) = 16h 59m 25s Dec(J2000) = +55d 22' 59" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows several overlapping peaks structure with a total duration of about 20 sec. The peak count rate was ~7000 counts/sec (15-350 keV), at ~4 sec after the trigger. Due to an observing constraint, Swift will not slew until T0+33.7 minutes. There will be no XRT or UVOT data until this time. The star tracker lost lock about 1 minute before the trigger, but the location should be good by propagating the gyros. INTEGRAL-SPIACS also saw this burst. Burst Advocate for this burst is R. L. C. Starling (rlcs1 AT star.le.ac.uk). 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.)