[vsnet-grb-info 2902] GRB 060211B: Swift-BAT detection of a burst

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4739
SUBJECT: GRB 060211B: Swift-BAT detection of a burst
DATE:    06/02/11 16:23:22 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <Scott at lheamail.gsfc.nasa.gov>

S. Mateos (U Leicester), S. Barthelmy (GSFC), N. Gehrels (GSFC),
O. Godet (U Leicester), C. Hurkett (U Leicster), J. Kennea (PSU),
H. Krimm (GSFC/USRA), F. Marshall (GSFC), J. Osborne (U Leicester),
K. Page (U Leicester), D. Palmer (LANL)
on behalf of the Swift team:

At 15:55:15 UT, Swift-BAT triggered and located GRB 060211B (trigger=181156).
The spacecraft slewed immediately.  The BAT on-board calculated location is
RA,Dec 75.069d,+14.958d {05h 00m 17s,+14d 57' 27"} (J2000), with an uncertainty
of 3 arcmin (radius, 90% containment, stat+sys).  The BAT light curve shows
two main peaks starting about 10 sec before the trigger and extending to T+15sec,
with a total duration of ~30 sec.  The peak count rate was ~1000 counts/sec
(15-350 keV), at ~0 seconds at the trigger.

The XRT began taking data at 15:56:38 UT, 83 seconds after the BAT trigger.
The XRT on-board centroid algorithm did not converge and no prompt position
is available.  The lightcurve shows evidence of a fading source.  We are
waiting for down-linked data to detect and determine a position for the source.

UVOT took a finding chart exposure of 200 seconds with the V filter starting
84 seconds after the BAT trigger.  No afterglow candidate has been found in the
initial data products.  The 2.7'x2.7' sub-image covers 25% of the BAT error
circle.  The typical 3-sigma upper limit has been about 18th mag.  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 18.0 mag.
No correction has been made for the expected extinction of about 1.4 magnitudes.