[vsnet-grb-info 5376] GRB 071112: Swift detection of a possible burst

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7057
SUBJECT: GRB 071112: Swift detection of a possible burst
DATE:    07/11/12 15:21:07 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott at lheamail.gsfc.nasa.gov>

G. Stratta (ASDC), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU),
G. Cusumano (INAF-IASFPA), C. Gronwall (PSU),
S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),
C. B. Markwardt (CRESST/GSFC/UMD), P. T. O'Brien (U Leicester),
K. L. Page (U Leicester), D. M. Palmer (LANL), A. M. Parsons (GSFC),
P. Romano (Univ. Bicocca & INAF-OAB), B. Sbarufatti (INAF-IASFPA),
T. N. Ukwatta (GSFC/GWU), D. E. Vanden Berk (PSU) and
S. D. Vergani (DIAS-DCU) report on behalf of the Swift Team:

At 14:51:39 UT, the Swift Burst Alert Telescope (BAT) triggered and
located possible GRB 071112 (trigger=296491).  Swift slewed immediately. 
The BAT on-board calculated location is 
RA, Dec 297.442, -50.338 which is 
   RA(J2000)  =  19h 49m 46s
   Dec(J2000) = -50d 20' 15"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a very weak peak
at T+0 (this was a 1-sec rate trigger) and then a 10-sec peak at ~T+40 sec. 
The peak count rate was ~1000 counts/sec (15-350 keV), at ~T+40 sec
after the trigger. 

The XRT began observing the field at 14:53:22 UT, 103 seconds after the
BAT trigger. XRT centroided on-board on a CCD hot column, so the position 
sent out in our first, automated XRT Position Notice is incorrect. 
>From preliminary ground analysis of an exposure of 1153 s of 
Photon Counting mode data, XRT did not find any X-ray source 
within the BAT error circle. 

UVOT took a finding chart exposure of nominal 100 seconds with the White
(160-650 nm) filter starting 112 seconds after the BAT trigger. No afterglow
candidate has been found in the initial data products. Image catalog data are
not available at this time. 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 extinction. 

Burst Advocate for this burst is G. Stratta (giulia.stratta AT asdc.asi.it). 
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.)