TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3961
SUBJECT: GRB050911: Swift-BAT detection of a long burst
DATE:    05/09/11 16:30:59 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <jayc@milkyway.gsfc.nasa.gov>

K. Page (U. Leicester), M. Chester (PSU), J. Cummings (GSFC/NRC),
N. Gehrels (GSFC), J. Kennea (PSU), C. Markwardt (GSFC/UMD), 
D. Palmer (LANL), T. Sakamoto (GSFC),
on behalf of the Swift team:

At 15:59:34 UT, Swift-BAT triggered and located GRB050911 (trigger=154630).
The BAT on-board calculated location is RA,Dec 13.692, -38.861
{00h 54m 46s, -38d 51' 37"} (J2000), with an uncertainty of 3 arcmin
(radius, 90% containment, stat+sys).  The BAT light curve shows multi-
peaks with short peaks (< 500 msec) at T-1 sec and T+0 sec, and a broader
peak between T+10 to T+20 sec.  The peak count rate was ~1000 counts/sec
(15-350 keV), at the time of the trigger. 

Due to the Earth limb observing constraint, the spacecraft could not slew
immediately.  The burst will become visible to the Narrow Field Instruments
at 16.52 UT (approximately 51 minutes after the trigger), at which point
XRT data will be obtained.