GCN Circular 14064

D. Grupe (PSU), W. H. Baumgartner (GSFC/UMBC),
C. Guidorzi (U Ferrara), H. A. Krimm (CRESST/GSFC/USRA),
C. B. Markwardt (NASA/GSFC), K. L. Page (U Leicester),
D. M. Palmer (LANL) and M. Stamatikos (OSU/NASA/GSFC) report on behalf
of the Swift Team:

At 06:56:13 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 121212A (trigger=541371).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 177.841, +78.034 which is 
   RA(J2000) = 11h 51m 22s
   Dec(J2000) = +78d 02' 04"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a FRED-like
structure with a duration of about 20 sec.  The peak count rate
was ~2300 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 06:57:21.7 UT, 68.4 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 177.78252, 78.03720 which is equivalent
to:
   RA(J2000)  = 11h 51m 07.80s
   Dec(J2000) = +78d 02' 13.9"
with an uncertainty of 4.1 arcseconds (radius, 90% containment). This
location is 45 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. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (3.67 x
10^20 cm^-2, Kalberla et al. 2005), with an excess column of 4.2
(+2.54/-2.19) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 71 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of
the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The 8'x8' region for the list of sources generated on-board covers 100% of the
BAT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.07. 

Burst Advocate for this burst is D. Grupe (dxg35 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/too.html.)