[vsnet-grb-info 21701] Swift Trigger 886157: Swift detection of a new transient Swift J1728.9-3613

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23800
SUBJECT: Swift Trigger 886157: Swift detection of a new transient Swift J1728.9-3613
DATE:    19/01/28 01:47:01 GMT
FROM:    Jamie A. Kennea at PSU/Swift-XRT  <kennea at swift.psu.edu>

S. D. Barthelmy (GSFC), A. D'Ai (INAF-IASFPA), V. D'Elia (SSDC),
J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), K. L. Page (U Leicester),
D. M. Palmer (LANL) and A. Tohuvavohu (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:

At 01:22:25 UT, the Swift Burst Alert Telescope (BAT) triggered and
located a new transient which we name Swift J1728.9-3613 (trigger=886157).  
The BAT on-board calculated location is 
RA, Dec 262.232, -36.237 which is 
   RA(J2000) = 17h 28m 56s
   Dec(J2000) = -36d 14' 13"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty). As is normal for an image trigger, the onboard
light-curve showed no significant structure. 

Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 09:11 UT on 2019 January 29. There will thus be no XRT
or UVOT data for this trigger before this time. 

The rise of this transient was seen by the BAT transient monitor
(Krimm et al., 2013), with the first detection on 2019 January 25. The BAT 
light-curve can found at the following link:   

https://swift.gsfc.nasa.gov/results/transients/weak/SWIFTJ1728.9-3613/SWIFTJ1728.9-3613.html