GCN Circular 4051

A. Moretti (OAB), J. Cummings (GSFC-NRC),
N. Gehrels (GSFC), S. Hunsberger (PSU), H. Krimm (GSFC-USRA),
C. Markwardt (GSFC-UMD), F. Marshall (GSFC), D. Palmer (LANL),
P. Romano (OAB),  on behalf of the Swift team:

GRB 051001:  Swift Detection of a Burst

At 11:11:36 UT, Swift-BAT triggered and located GRB051001
(trigger=157870). The spacecraft slewed immediately, which in
this case was 75 seconds after the image trigger.  The BAT
on-board calculated location is RA,Dec 350.973d, -31.528d
{23h 23m 53s, -31d 31' 39"} (J2000), with an uncertainty
of 3 arcmin (radius, 90% containment, stat+sys).  Since this
was an image trigger there is no obvious information in the light curve.

XRT began observing the field at 11:14:42, 185 seconds after the
BAT trigger.  Onboard centroiding found a bright fading uncatalogued
X-ray source in the field of view at the following coordinates:
RA(J2000):   23h 23m 49.1
Dec(J2000):  -31d 31' 15.6"
We estimate the uncertainty of this position to be 6 arcseconds
(radius, 90%  containment).  This position is 61 arcseconds
from the BAT position above.

UVOT began observing the field 189 seconds after the trigger.
The small image does not overlap the XRT error circle.
No new source was seen in the list of sources from the entire
UVOT field of view.

We are currently in the portion of the orbits where the spacecraft
does not pass over the Malindi downlink station.  Therefore, it will
be at least four hours before we have access to the full data set
for the refined analyses.