TITLE:   GCN CIRCULAR
NUMBER:  20335
SUBJECT: Swift Trigger 728268: a possible GRB
DATE:    16/12/24 22:29:04 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

A. Cholden-Brown (PSU), S. D. Barthelmy (GSFC),
N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL)
and A. Y. Lien (GSFC/UMBC) report on behalf of the Swift Team:

At 22:13:34.64 UT, the Swift Burst Alert Telescope (BAT) triggered and
located a possible source (trigger=728268).  Swift did not slew
to the location because it is Moon-constrained. 
The BAT on-board calculated location is 
RA, Dec 204.825, -18.028, which is 
   RA(J2000)  = +13h 39m 18s
   Dec(J2000) = -18d 01' 41"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty). The light curve shows a weak bump from ~T+25 to ~T+50 sec. 

Due to a Moon observing constraint, Swift cannot slew to the BAT
position until 00:54 UT on 2016 December 25. There will thus be no XRT
or UVOT data for this trigger before this time. 

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.)