GCN Circular 43005

S. Lanava (PSU), S. Dichiara (PSU), C. Gronwall (PSU),
R. Gupta (NASA GSFC), N. P. M. Kuin (UCL-MSSL), A. Y. Lien (U Tampa),
D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:

At 23:39:47 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 251205A (trigger=1420873).  Swift slewed immediately to the burst.
The BAT on-board calculated location is 
RA, Dec 200.243, +29.962 which is 
   RA(J2000) = 13h 20m 58s
   Dec(J2000) = +29d 57' 45"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a complex
structure with a duration of about 30 sec.  The peak count rate
was ~500 counts/sec (15-350 keV), at ~0 sec after the trigger.

The XRT began observing the field at 23:42:07.0 UT, 139.8 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 200.2707, 29.9296 which is equivalent to:
   RA(J2000)  = 13h 21m 4.97s
   Dec(J2000) = +29d 55' 46.6"
with an uncertainty of 5.3 arcseconds (radius, 90% containment). This
location is 145 arcseconds from the BAT onboard position, within the
BAT error circle. No event data are yet available to determine the
column density using X-ray spectroscopy.

The initial flux in the 2.5 s image was 1.44e-09 erg cm^-2 s^-1 (0.2-10
keV).

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 148 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  =	13:21:05.34 = 200.27223
  DEC(J2000) = +29:55:44.0  =  29.92888
with a 90%-confidence error radius of about 0.75 arc sec. This position is 5.4
arc sec. from the center of the XRT error circle. The estimated magnitude is
17.54 with a 1-sigma error of about  0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.014.

Burst Advocate for this burst is S. Lanava (sml7284 AT 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/)