[vsnet-grb-info 20579] Swift Trigger 829046 is probably noise

GCN Circulars gcncirc at capella2.gsfc.nasa.gov
Thu Apr 26 22:43:53 JST 2018


TITLE:   GCN CIRCULAR
NUMBER:  22677
SUBJECT: Swift Trigger 829046 is probably noise
DATE:    18/04/26 13:43:12 GMT
FROM:    David Palmer at LANL  <palmer at lanl.gov>

P. D'Avanzo (INAF-OAB), J.D. Gropp (PSU), J. A. Kennea (PSU),
A. Melandri (INAF-OAB), K. L. Page (U Leicester), M. H. Siegel (PSU)
and A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 13:18:35 UT, the Swift Burst Alert Telescope (BAT) detected a low
significance image peak in an untriggered image. Because the image 
peak was near the line of sight to a nearby galaxy, BAT alerted 
Swift (trigger=829046).  Swift could not slew to the location
due to an Earth limb constraint. 
The BAT on-board calculated location is 
RA, Dec 57.459, -48.782 which is 
   RA(J2000) = 03h 49m 50s
   Dec(J2000) = -48d 46' 53"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows no activity,
which is consistent with an image trigger with or without a weak source. 

Due to the observing constraint, there are no immediately available
XRT or UVOT data. 

Due to the marginal significance of the image peak (5.86 sigma),
the lack of a rate trigger or rate variation in the available
lightcurve, and the distance of the image peak from the potential
host (8 arcminutes) we believe that this is a statistical fluctuation
in image space and not an astrophysical source. 



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