GCN Circular 16002
Subject
Swift Trigger 592558 is not an astrophysical source
Date
2014-03-20T06:43:54Z (11 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
C. J. Mountford (U Leicester), K. L. Page (U Leicester) and
D. M. Palmer (LANL) report on behalf of the Swift Team:
At 06:11:00 UT, the Swift Burst Alert Telescope (BAT) found a
marginal-significance peak (5.83 sigma) in a non-rate-triggered
64 second image (trigger=592558). Because the peak location was close
(8.5 arcminutes) to a nearby galaxy, Swift slewed immediately to the
location to make a confirmation observation with the narrow-field instruments.
The BAT on-board calculated location is
RA, Dec 190.636, +11.579 which is
RA(J2000) = 12h 42m 33s
Dec(J2000) = +11d 34' 44"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). The BAT light curve shows no obvious count
rate variation.
The XRT began observing the field at 06:13:02.6 UT, 122.5 seconds after
the BAT trigger. No source was detected in 1.2 ks of promptly
downlinked data, which covered 97% of the BAT error circle.
Given the sub-threshold nature of the trigger, the lack of features in
the BAT light-curve and the fact that no X-ray source is detected, we
believe this was just a noise event.