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GCN Circular 11553

Subject
GRB 110112A: Swift detection of a possible short burst
Date
2011-01-12T04:26:58Z (13 years ago)
From
Michael Stamatikos at OSU/GSFC <michael.stamatikos-1@nasa.gov>
M. Stamatikos (OSU/NASA/GSFC), A. P. Beardmore (U Leicester),
J. R. Cummings (NASA/UMBC), J. M. Gelbord (PSU),
S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),
O. M. Littlejohns (U Leicester), K. L. Page (U Leicester),
J. L. Racusin (NASA/GSFC), T. Sakamoto (NASA/UMBC),
M. H. Siegel (PSU), E. Sonbas (GSFC/USRA/Adiyaman Univ.) and
E. Troja (NASA/GSFC/ORAU) report on behalf of the Swift Team:

At 04:12:18 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 110112 A (trigger=442039).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 329.941, +26.489 which is 
   RA(J2000) = 21h 59m 46s
   Dec(J2000) = +26d 29' 20"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single peak 
with a duration of about 2 sec.  The peak count rate
was ~1700 counts/sec (15-350 keV), at the trigger time. 

The XRT began observing the field at 04:13:33.9 UT, 75.5 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 329.9330, 26.4564 which
is equivalent to:
   RA(J2000)  = 21h 59m 43.91s
   Dec(J2000) = +26d 27' 23.0"
with an uncertainty of 2.7 arcseconds (radius, 90% containment). This
location is 119 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 5.54
x 10^20 cm^-2 (Kalberla et al. 2005). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 80 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 none of
the XRT error circle. The coverage of the XRT error circle by the 8'x8' region
for the list of sources generated on-board is uncertain because the large
number of sources filled the available telemetry. No correction has been made
for the expected extinction corresponding to E(B-V) of 0.06. 

Burst Advocate for this burst is M. Stamatikos (Michael.Stamatikos-1 AT nasa.gov). 
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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