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GCN Circular 12920

Subject
GRB 120211A: Swift detection of a burst
Date
2012-02-11T12:10:51Z (12 years ago)
From
David Palmer at LANL <palmer@lanl.gov>
E. Sonbas (NASA/GSFC/Adiyaman Univ.), W. H. Baumgartner (GSFC/UMBC),
D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), E. A. Hoversten (PSU),
V. Mangano (INAF-IASFPA), C. Pagani (U Leicester),
K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of
the Swift Team:

At 11:58:28 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 120211A (trigger=514586).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 87.751, -24.759 which is 
   RA(J2000) = 05h 51m 00s
   Dec(J2000) = -24d 45' 32"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single-peaked
structure with a duration of about 30 sec.  The peak count rate
was ~300 counts/sec (15-350 keV), at ~3 sec after the trigger. 

The XRT began observing the field at 12:00:27.6 UT, 119.5 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source located at RA, Dec 87.75354, -24.77477 which
is equivalent to:
   RA(J2000)  = 05h 51m 00.85s
   Dec(J2000) = -24d 46' 29.2"
with an uncertainty of 3.9 arcseconds (radius, 90% containment). This
location is 57 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 consistent with the Galactic value of 1.73
x 10^20 cm^-2 (Kalberla et al. 2005). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 123 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 100% of
the XRT 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
XRT 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
0.03. 

Burst Advocate for this burst is E. Sonbas (edasonbas AT yahoo.com). 
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.)
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