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GCN Circular 9739

Swift trigger 358760 is probably a noise event
2009-07-31T12:59:40Z (15 years ago)
Scott Barthelmy at NASA/GSFC <>
B. Sbarufatti (INAF-IASFPA), S. D. Barthelmy (GSFC),
P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC),
C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC),
E. A. Hoversten (PSU), J. A. Kennea (PSU), V. Mangano (INAF-IASFPA),
C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester), P. Romano (INAF-IASFPA),
T. Sakamoto (NASA/UMBC), M. A. Stark (PSU),
R. L. C. Starling (U Leicester) and T. N. Ukwatta (GSFC/GWU) report
on behalf of the Swift Team:

At 12:46:30 UT, the Swift Burst Alert Telescope (BAT) triggered
(trigger=358760) on a probable noise event.  Swift slewed immediately
to the location.  The BAT on-board calculated location is 
RA, Dec 189.691, -15.409, which is 
   RA(J2000)  =  12h 38m 46s
   Dec(J2000) = -15d 24' 31"
with an uncertainty of 4 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows nothing significant. 

The XRT began observing the field at 12:47:35.3 UT, 64.4 seconds after
the BAT trigger. No source was detected in the promptly available XRT
data. We are waiting for the full dataset to detect and localise the
XRT counterpart. 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 67 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. Data from the 2.7'x2.7' sub-image are
not available at this time. 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 0.05. 

We will need to wait for the full data set (in a few hours)
to be able to make a final determination on the identity
of this trigger.
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