TITLE:   GCN CIRCULAR
NUMBER:  33432
SUBJECT: Swift Trigger 1159108 is not a GRB
DATE:    23/03/09 06:37:08 GMT
FROM:    Kim Page at U.of Leicester  <kimlpage1978@gmail.com>

P. D'Avanzo (INAF-OAB), M. Ferro (INAF-OAB), K. L. Page (U Leicester),
T. M. Parsotan (GSFC/UMBC/CRESSTII), C. Salvaggio (INAF-OAB),
T. Sbarrato (INAF-OAB), B. Sbarufatti (INAF-OAB), M. H. Siegel (PSU)
and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels
Swift Observatory Team:

At 06:16:27 UT, the Swift Burst Alert Telescope (BAT) triggered and 
Swift slewed immediately to the trigger. 
The BAT on-board calculated location is 
RA, Dec 45.888, +0.625 which is 
   RA(J2000) = 03h 03m 33s
   Dec(J2000) = +00d 37' 32"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT triggered on a 65 ms rate trigger with a
significance less than 7 sigma and the resulting detector plane image also 
showed a peak with less than 7 sigma significance. 

The XRT began observing the field at 06:17:41.7 UT, 74.8 seconds after
the BAT trigger. No source was detected in the 2.5-s promptly available
image. 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 78 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of
the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The 8'x8' region for the list of sources generated on-board covers 100% of the
BAT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.082.