GCN Circular 3509

A. Retter (PSU), A. Parsons, N. Gehrels (GSFC), C. Gronwall (PSU),
C. B. Markwardt (GSFC/UMD),  D. Palmer (LANL)

on behalf of the Swift Team report:


At 06:29:05 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB050603 (trigger=131560).   The BAT on-board calculated
location is RA,Dec  39.978 (+02h 39m 55s), -25.183 (-25d 10' 57")
(J2000) with an uncertainty of 4 arcmin (radius, 3-sigma, including
estimated systematic uncertainty).  The peak rate was
22,000 counts/sec in 0.512 sec in the 50 - 350 keV band.

The Swift spacecraft did not slew because automated slewing was not
enabled due to engineering  tests. XRT and UVOT observations will be
performed after the analysis of the ground data. This burst is near
the edge of the FOV (~8% coding) and so it is brighter than indicated
by the nominal peak count rate.

No light curves will be available until the next Malindi ground contact
data is received and analyzed.  However, during the approximately 7
seconds of image processing, no subsequent interval was found with a more
significant rate increase than the initial 0.512 s trigger (although 
further emission at lower levels is not precluded by the data available 
at this time.) Thus preliminary indications suggest that this might be 
a bright short-hard burst.