[vsnet-grb-info 19280] Swift Trigger 745090 is a noise trigger near NGC 5195

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20972
SUBJECT: Swift Trigger 745090 is a noise trigger near NGC 5195
DATE:    17/04/02 10:53:27 GMT
FROM:    Boris Sbarufatti at INAF-OAB/IASFPA  <boris.sbarufatti at brera.inaf.it>

S. D. Barthelmy (GSFC), P. D'Avanzo (INAF-OAB),
A. Y. Lien (GSFC/UMBC), A. Melandri (INAF-OAB),
K. L. Page (U Leicester) and B. Sbarufatti (INAF-OAB/PSU) report on
behalf of the Swift Team:

At 10:33:41 UT, the Swift Burst Alert Telescope (BAT) triggered on noise
near NGC 5195 (trigger=745090).  Swift slewed immediately to the location. 
The BAT on-board calculated location is 
RA, Dec 202.405, +47.358, which is 
   RA(J2000)  =  13h 29m 37s
   Dec(J2000) = +47d 21' 27"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  As is typical for image triggers, the real-time
light curve does not show anything significant.  This is a low-significance
trigger (6.24 sigma) on noise in the on-board image near NGC 5195.  It is not
an astrophysical event. 

The XRT began observing the field at 10:36:10.0 UT, 149.0 seconds after
the BAT trigger. No source was detected in 575 s of promptly downlinked
data. 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 153 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
0.03.