TITLE:   GCN CIRCULAR
NUMBER:  20333
SUBJECT: Swift Trigger 728094: a possible GRB
DATE:    16/12/23 19:29:31 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

A. Cholden-Brown (PSU), S. D. Barthelmy (GSFC),
A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL), M. H. Siegel (PSU) and
T. N. Ukwatta (LANL) report on behalf of the Swift Team:

At 19:01:26 UT, the Swift Burst Alert Telescope (BAT) triggered and
located a possible source (trigger=728094).  Swift did not slew
to the location because it is Sun-constrained. 
The BAT on-board calculated location is 
RA, Dec 259.877, -25.010 which is 
   RA(J2000)  =  17h 19m 31s
   Dec(J2000) = -25d 00' 36"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty). Because of the duration of the image trigger
(8.3 minutes) no BAT lightcurve data is immediately available. 

Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 13:22 UT on 2017 January 27. There will thus be no XRT
or UVOT data for this trigger before this time. 

Since this is a long image trigger and we have no BAT light curve information
nor do we have any XRT and UVOT data because of the Sun constraint,
all we can say at this time is that it is about equal probability
that it is noise (image significance is 7.6 sigma), or a GRB, or
another type of astrophysical source.  We note that it is ~7 deg
from the Galactic Center. 

Burst Advocate for this burst is A. Cholden-Brown (aaronb AT swift.psu.edu). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)

[GCN OPS NOTE(23dec16):  Per author's request, we corrected the second 
sentence in the first paragraph.  We did not slew because the location
was Sun-constrained.]