GCN Circular 3525

A. Retter, J. Racusin, J. Kennea, D. Burrows (PSU), D. Palmer (LANL),
K. McGowan (MSSL), J. Cummings (NRC/GSFC), S. Barthelmy, N. Gehrels
(GSFC)

on behalf of the Swift Team report:

At 09:11:23 UT the Swift-BAT triggered on GRB 050607 (trigger 132247).
The BAT refined ground position is RA, Dec 300.167, +9.137 (J2000)
{20h00m40s, +09d 08' 13"}.  The burst had 3 peaks over 30 seconds, with a
T90 of 26.5 seconds from T+0 to T+26.5 seconds. Its spectrum is well fit
by a simple power law with an index of 1.93 +/- 0.14.  The total fluence
was (8.9 +/- 1.2) x 10^-7 erg/cm2 over 15-350 keV. The peak flux was
1.15+/-0.16 photons/cm2/s from T+1 to T+2 seconds. The burst was 27
degrees off the BAT boresight in the 87% coded field of view. Swift slewed
to the position of the burst immediately, starting 17 seconds after the
burst trigger.


The XRT was pointed promptly at the burst at 09:13:02 UT (100 s after the
BAT burst trigger).  The XRT did not centroid on-board, but ground
analysis revealed a bright X-ray source near the center of the field of
view, with position RA(J2000) = 20h 00m 42.5s Dec(J2000) = +09d 08' 30''
We estimate an uncertainty of approximately 8 arcseconds radius (90%
containment).  This position is 40 arcseconds from the BAT position.


Immediate data from UVOT will not be available due to the instrument
being in an engineering mode.