[vsnet-grb-info 1750] GRB 050713B

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3590
SUBJECT: GRB 050713B
DATE:    05/07/13 13:09:51 GMT
FROM:    Simon Vaughan at Leicester U/BA  <sav2 at star.le.ac.uk>

S. Vaughan (Leicester), A. Falcone (PSU), D. Palmer (LANL),
A. Blustin (MSSL), S. Barthelmy (GSFC), J. Cummings
(GSFC/NRC), H. Krimm (GSFC/USRA), D. Burrows, D. Morris, C.
Gronwall (PSU), C. Markwardt (GSFC/UMD), K. Page, M. Goad
(Leicester), S Rosen (MSSL), N. Gehrels (GSFC)

At 12:07:17.62 UT, the Swift Burst Alert Telescope (BAT)
triggered and located on-board GRB050713B (trigger=145754).
The spacecraft slewed immediately.  The flight-determined
location is RA,Dec 307.843,+60.920 {20h 31m 22s,+60d 55'
12"} (J2000) with an uncertainty of 3 arcmin (radius, 90%
c.l. stat+sys).  The burst lightcurve has 1 (maybe 2) peaks
within ~30 sec duration.  It is riding on top of two long
bumps which are believed to be background, but without the
full Malindi data, we can not determine if the bumps are
background or burst-related. The peak rate (without bumps)
is ~1000 cnts/sec in the 15-350 keV band.

The spacecraft slewed immediately and the XRT began
observing the burst at 12:09:33 UT (136 s after the BAT
trigger). XRT found a bright, uncataloged, fading X-ray
source at:

RA:  +20h 31m 15.5s (J2000),
DEC: +60d 56' 38.4" (J2000).

This position is 100 arcseconds from the BAT position.  The
estimated uncertainty is 6 arcseconds radius (90%
containment).

The Swift Ultra Violet/Optical Telescope (UVOT) observations
began at 12:09:33 UT, 136 seconds after the BAT trigger.
The first data taken after the spacecraft settled was a 100
sec exposure using the V filter with the midpoint of the
observation at 186 sec after the BAT trigger. Based on
comparisons to the DSS, we detect no new source at the XRT
position.