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GCN Circular 32887

Subject
Trigger 1132968: Swift trigger is the Crab
Date
2022-10-29T13:39:34Z (2 years ago)
From
Simone Dichiara at PSU <sbd5667@psu.edu>
S. Dichiara (PSU), J. A. Kennea (PSU) and A. Y. Lien (U Tampa) report
on behalf of the Neil Gehrels Swift Observatory Team:

At 06:48:50 UT, the Swift Burst Alert Telescope (BAT) triggered (trigger #1132968)
that was identified as Crab. However, the BAT transient monitor does not
show any significant activity of the Crab. Also, this trigger
is a 12.7-min long image trigger, similar to the condition of
previous erroneous triggers due to a known race condition
in the Swift/BAT software. Therefore, we believe this trigger
is not due to interesting activity of the Crab. The full ground data
is required to confirm the nature of this trigger.

The XRT began observing the field at 12:23:53.1 UT, 1087.3 seconds
after the BAT trigger. XRT's onboard centroiding algorithm did not
find a point source in the field of view, however as the Crab is an
extended source, this is as expected.
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