[vsnet-grb-info 9091] Trigger 419015 is probably not a GRB

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  10578
SUBJECT: Trigger 419015 is probably not a GRB
DATE:    10/04/10 07:58:09 GMT
FROM:    David Palmer at LANL  <palmer at lanl.gov>

S. Immler (CRESST/GSFC/UMD), C. Guidorzi (U Ferrara),
H. A. Krimm (CRESST/GSFC/USRA), V. Mangano (INAF-IASFPA),
C. B. Markwardt (CRESST/GSFC/UMD), D. M. Palmer (LANL),
P. Romano (INAF-IASFPA), B. Sbarufatti (INAF-OAB/IASFPA) and
M. A. Stark (PSU) report on behalf of the Swift Team:

At 07:27:40 UT, the Swift Burst Alert Telescope (BAT) triggered
on trigger 419015.  Swift slewed immediately to this location. 
The BAT on-board calculated location is 
RA, Dec 293.310, -34.309 which is 
   RA(J2000) = 19h 33m 14s
   Dec(J2000) = -34d 18' 30"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows that this trigger 
occurred on the run up to the SAA and includes nothing significant 
at the trigger time. 

The XRT began observing the field at 07:28:39.9 UT, 59.3 seconds after
the BAT trigger. No convincing point source is visible in the field of view. 

Due to passage into the SAA after the trigger, no prompt UVOT data is
available. 

Given that this trigger occurred during the run-up to the SAA,
the lack of a peak in the BAT rate light curve at the
time of a trigger, and the lack of an XRT source, we
currently believe that this source is not an astrophysical
GRB.  Confirmation of this will require the data from after
the spacecraft emerges from the SAA, and the data available
from the Malindi downlink.