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 3999

Swift-BAT trigger 155764 is probably not a GRB
2005-09-18T20:29:07Z (19 years ago)
Scott Barthelmy at NASA/GSFC <>
D. Grupe (PSU), S. Barthelmy (GSFC), D. Burrows (PSU), N. Gehrels (GSFC),
H. Krimm (GSFC/USRA), J. Kennea (PSU), C. Markwardt (GSFC/UMD),
D. Palmer (LANL), P. Roming (PSU)
on behalf of the Swift team:

The Swift-BAT trigger (trigger=155764) at 19:42:13 UT on 18 Sep 2005
is probably not due to a GRB or any other astrophysical source.
We will have the full data set at 23:45 UT, after which we will issue
a final determination.

The spacecraft slewed immediately and the XRT began observing at 19:43:11 
(at T+58s).  The XRT generated an on-board centroid on a cosmic ray near 
the edge of the field of view.  This position is invalid (GCN 3998).
The spectrum and light curve are ambiguous, and we cannot rule out
the possibility of a weak afterglow in the XRT field of view.
Further analysis will require downloaded data following the next
ground station pass.

[GCN OPS NOTE(18sep05): Per author's request, the trigger number
in the subject line was corrected.]
Looking for U.S. government information and services? Visit