[vsnet-grb-info 7414] Swift trigger 346250 is probably not a burst

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8978
SUBJECT: Swift trigger 346250 is probably not a burst
DATE:    09/03/12 06:52:08 GMT
FROM:    Hans Krimm at NASA-GSFC  <krimm at milkyway.gsfc.nasa.gov>

H. A. Krimm (CRESST/GSFC/USRA), E. A. Hoversten (PSU),
C. B. Markwardt (CRESST/GSFC/UMD), K. L. Page (U Leicester) and
L. Vetere (PSU) report on behalf of the Swift Team:

On 2009-03-12 at 06:17:00 UT, the Swift Burst Alert Telescope (BAT) 
triggered on Swift trigger 346250.  Swift did not slew immediately to the event
due to an earth-limb constraint. The BAT on-board calculated location
is RA, Dec 282.112, +36.758 which is 
   RA(J2000) = 18h 48m 27s
   Dec(J2000) = +36d 45' 28"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed nothing significant. 
Given the low significance (5.72 sigma) we do not believe that this event
is a real GRB.  Swift will not be able to observe with the Swift narrow-field
instruments until ~48 minutes after the trigger.