Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 20480

Swift Trigger #733426: possible detection of a burst or transient
2017-01-17T23:14:38Z (7 years ago)
David Palmer at LANL <>
Swift Trigger #733426: possible detection of a burst or transient

D. M. Palmer (LANL) 
reports on behalf of the Swift team:

At 2017-01-17 03:37:48 UT, the Swift Burst Alert Telescope (BAT)
took a series of waiting mode images that showed peaks of marginal
significance, recognized in further ground analysis as a possible
unknown source or GRB (Triggers #733426-#733430, GRB 170117A).
The most significant image showed a peak at a BAT on-board calculated 
location RA, Dec 61.589, +21.743 which is 
  RA(J2000) = 04h 06m 21s
  Dec(J2000) = +21d 44' 35"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The onboard images show a maximum flux
level over the T+240 s to T+304 s time interval, while the maximum
significance is found over the T+0 s to T+672 s image covering
the entire pointing interval.

Due to the marginal significance (maximum 6.5 sigma) of the
image peak detection, the reality of this detection is uncertain.
Its several-minute or longer duration is longer than usual for a GRB,
but its distance from the Galactic plane (l,b ~ 172,-22) would
be unusual for a Galactic transient.  Therefore, both the
reality and category of this source are uncertain.

A Swift Target of Opportunity follow-up has been requested.
Looking for U.S. government information and services? Visit