[vsnet-grb-info 2792] GRB 060202: Swift detection of a burst

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4629
SUBJECT: GRB 060202: Swift detection of a burst
DATE:    06/02/02 09:33:04 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <Scott at lheamail.gsfc.nasa.gov>

D. Fox (PSU), S. Barthelmy (GSFC), D. Burrows (PSU), J. Cummings (GSFC/NRC),
N. Gehrels (GSFC), S.T. Holland (GSFC/USRA), S. Hunsberger (PSU),
H. Krimm (GSFC/USRA), D. Morris (PSU), D. Palmer (LANL)
on behalf of the Swift team:

At 08:40:55 UT, Swift-BAT triggered and located GRB 060202 (trigger=179968).
The spacecraft slewed immediately.  The BAT on-board calculated location
is RA,Dec 35.843d,+38.362d {02h 23m 22s,+38d 21' 43"} (J2000),
with an uncertainty of 3 arcmin (radius, 90% containment, stat+sys).
This was a 64-sec image trigger.  The BAT light curve shows a broad and
weak peak with a total duration of >20 sec.  The peak count rate was
~500 counts/sec (15-350 keV), at ~5 seconds after the trigger.

XRT began observing the GRB at 08:43:18 UT, 143.3s after the BAT trigger.
A bright, uncatalogued, fading source, was found by the on-board
centroiding algorithm at
RA(J2000)=02h 23m 23.1s
DEC(J2000)=+38d 23' 09.2"
with an uncertainty of 6 arcseconds radius (90% containment).
This position lies 87 arcseconds from the center of the BAT error
circle.  The XRT count rate clearly decreases as a power law
in the first 100s.  The initial XRT flux was ~2.5E-8 ergs/cm2/s.

UVOT took a finding chart exposure of 200 seconds with the V filter
starting 148 seconds after the BAT trigger.  No afterglow candidate has
been found in the initial data products.  The 2.7'x2.7' sub-image covers
100% of the XRT 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 XRT 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 0.2 magnitudes.