GCN Circular 23145
Subject
Swift Trigger 853790 is probably not an astrophysical source
Date
2018-08-17T21:16:48Z (7 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (PSU) and
M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:
At 20:58:18 UT, the Swift Burst Alert Telescope (BAT) triggered on a
low significance image peak near the line of sight to a nearby
galaxy (trigger=853790). Swift did not slew due to an observing
constraint. The BAT on-board calculated location is
RA, Dec 192.885, +25.921 which is
RA(J2000) = 12h 51m 32s
Dec(J2000) = +25d 55' 15"
with an uncertainty of 3 arcmin (radius, 90% containment, including
systematic uncertainty). As is typical for an image trigger, there
no obvious structure in the immediately available lightcurve.
This position is too close to the Sun for Swift to observe until
2018 November 02. Thus there will be no XRT or UVOT data for this
trigger.
Due to the low significance of the image peak (6.1 sigma on-board,
with an even lower significance in the ground analysis of the
immediately-available detector plane data), the
lack of a rate trigger, and the offset from the putative
nearby galaxy (9 arcminutes) we believe that this is probably
just a statistical fluctuation in the image plane and not
an astrophysical source. The complete downlinked BAT data will
be used to confirm or refute this. There will be no XRT or UVOT
follow-up due to the observing constraint.