[vsnet-grb-info 6268] Swift trigger 314975 is not a GRB

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7893
SUBJECT: Swift trigger 314975 is not a GRB
DATE:    08/06/22 13:10:03 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott at lheamail.gsfc.nasa.gov>

K. McLean (GSFC/UMD), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
S. Immler (CRESST/GSFC/UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD),
K. L. Page (U. Leicester), D. Palmer (LANL), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the BAT data set from T-239 to T+963 sec from recent telemetry downlinks,
we report further analysis of trigger #314975 (Immler, et al., GCN Circ. 7892).
Ground processing of the full data set does not show any significant emission.
There is a pair of cosmic ray shower events within the trigger time interval plus
a small ~3-sigma fluctuation in the 25-100 keV band.

The XRT did not detect any sources, down to a conservative 3-sigma upper limit
of 2.5x10^-3 count s^-1 (using 3.4 ks of data obtained between 2 and 15 hours
after the trigger).

Given no other indications within the data, we conclude that this trigger
was caused by these temporally coincident noise events and not due to
anything astrophysical.