Skip to main content
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 26252

Swift Trigger 937114 is not an astrophysical source
2019-11-15T11:50:53Z (5 years ago)
David Palmer at LANL <>
A. P. Beardmore (U Leicester), C. Gronwall (PSU), J.D. Gropp (PSU),
J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester), D. M. Palmer (LANL) and
A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 11:26:20 UT, the Swift Burst Alert Telescope (BAT) triggered and
located an image peak due to a noisy detector element (trigger=937114).  
Swift slewed after a delay to clear an observing constraint. 
The BAT on-board calculated location is 
RA, Dec 292.179, +38.730 which is 
   RA(J2000) = 19h 28m 43s
   Dec(J2000) = +38d 43' 50"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve is difficult to interpret
due to the presence of the noisy detector element.  The full downlinked
data will allow the noisy element to be removed from analysis. 

The XRT began observing the field at 11:37:43.9 UT, 683.2 seconds after
the BAT trigger. No source was detected in 318 s of promptly downlinked
data. We are waiting for the full dataset to detect and localise the
XRT counterpart. 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 686 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of
the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The 8'x8' region for the list of sources generated on-board covers 100% of the
BAT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
Looking for U.S. government information and services? Visit