GCN Circular 18599

M. H. Siegel (PSU), S. D. Barthelmy (GSFC), N. P. M. Kuin (UCL-MSSL),
L. M. McCauley (PSU) and B. Sbarufatti (INAF-OAB/PSU) report on behalf
of the Swift Team:

At 09:59:34 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 151114A (trigger=663490).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 120.937, -61.042, which is 
   RA(J2000)  =  08h 03m 45s
   Dec(J2000) = -61d 02' 31"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a couple peaks
with a duration of about 20 sec.  The peak count rate
was ~2000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 10:01:03.9 UT, 89.8 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 120.94436, -61.02743 which is
equivalent to:
   RA(J2000)  = 08h 03m 46.65s
   Dec(J2000) = -61d 01' 38.7"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 53 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper.  We
cannot determine whether the source is fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 2.01
x 10^21 cm^-2 (Willingale et al. 2013). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 94 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  =	08:03:46.33 = 120.94305
  DEC(J2000) = -61:01:40.0  = -61.02779
with a 90%-confidence error radius of about 0.63 arc sec. This position is 1.4
arc sec. from the center of the XRT error circle. The estimated magnitude is
18.84 with a 1-sigma error of about  0.15. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.17. 

Burst Advocate for this burst is M. H. Siegel (siegel 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.)