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GCN Circular 23550

Subject

Trigger 878548: Swift detection of AX 1631.9-4752

Date

2018-12-23T03:05:46Z (5 years ago)

From

Amy Lien at GSFC <amy.y.lien@nasa.gov>

P. D'Avanzo (INAF-OAB), A. Y. Lien (GSFC/UMBC), B. Sbarufatti (PSU)
and A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 02:47:21 UT, the Swift Burst Alert Telescope (BAT) triggered and
located on the high mass X-ray binary AX 1631.9-4752 (trigger=878548).  
Swift did not slew to the source due to an observing constraint. 
The BAT on-board calculated location is 
RA, Dec 247.818, -47.818 which is 
   RA(J2000) = 16h 31m 16s
   Dec(J2000) = -47d 49' 02"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  As is typical for image triggers, the realtime
light curve does not show anything significant. 

The flare can also be seen in the BAT transient monitor 
(Krimm et al, 2013, ApJS, 209, 14; 15-50 keV):
https://swift.gsfc.nasa.gov/results/transients/AXJ1631.9-4752/

Due to a Sun observing constraint, Swift cannot slew to the BAT
position until January 14 2019. There will thus be no XRT or
UVOT data for this trigger before this time.