[vsnet-grb-info 2591] Swift-BAT trigger 175653 is not an astrophysical source

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4428
SUBJECT: Swift-BAT trigger 175653 is not an astrophysical source
DATE:    06/01/03 21:23:27 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <Scott at lheamail.gsfc.nasa.gov>

D. Grupe (PSU), S. Barthelmy (GSFC), T. Sakamoto (GSFC/NRC), M. Chester (PSU),
F. Marshall (GSFC), N. Gehrels (GSFC), D. Burrows (PSU), J. Kennea (PSU),
A. Retter (PSU)
on behalf of the Swift team:

We have analyzed the full BAT data set.  Trigger 175653
(Grupe et al. 2006, GCN 4426) is due to (a) a chance fluctuation 
in the rate domain, (b) superposed on a rising background 
while entering the SAA, or (c) a chance fluctuation in the image domain. 
The spacecraft slewed immediately to the BAT position, but
because the spacecraft was in the SAA, XRT only took a 2s image 
which did not show any bright source.  XRT started observing again
on 2006-January-03 05:19 UT about 75 minutes after the trigger.
This data set has a total observing time of 3.6 ks.  We do not find 
any source within the 3 arcmin BAT error circle. No afterglow candidate 
was identified by UVOT's automated processing either.

Therefore we consider this trigger as false and not due to a GRB or 
any astrophysical source.