[vsnet-grb-info 4258] GRB 070129: Swift detection of a burst

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6053
SUBJECT: GRB 070129: Swift detection of a burst
DATE:    07/01/29 23:49:36 GMT
FROM:    David Burrows at PSU/Swift  <dxb15 at psu.edu>

O. Godet (U Leicester), D. N. Burrows (PSU), M. M. Chester (PSU),
S. T. Holland (CRESST/GSFC/USRA), J. A. Kennea (PSU),
C. B. Markwardt (GSFC/UMD), K. M. McLean (LANL/UTD),
K. L. Page (U Leicester), D. M. Palmer (LANL),
T. Sakamoto (NASA/ORAU), M. Stamatikos (NASA/ORAU),
R. L. C. Starling (U Leicester), E. Troja (INAF-IASFPA),
D. E. Vanden Berk (PSU) and S. D. Vergani (DIAS-DCU) report on behalf
of the Swift Team:

At 23:35:10 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 070129 (trigger=258408).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 37.014, +11.697 which is 
   RA(J2000) = 02h 28m 03s
   Dec(J2000) = +11d 41' 51"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows no obvious
variation in the count rate, which is not uncommon for image
triggers. 

The XRT began observing the field at 23:37:23 UT, 134 seconds after the
BAT trigger. XRT found a bright, fading, uncatalogued X-ray source
located at RA, Dec 37.0033, +11.6852 which is
   RA(J2000)  =  02h 28m 00.7s
   Dec(J2000) =  11d 41' 06.7"
with an uncertainty of 4.7 arcseconds (radius, 90% containment). 
This location is 57 arcseconds from the BAT on-board position,
within the BAT error circle. The initial flux in the 2.5s image
was 3.3e-09 erg/cm2/s (0.2-10 keV). 

UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm)
filter starting 143 seconds after the BAT trigger. No afterglow candidate has
been found in the initial data products. The overlap of the sub-image and the
XRT error circle is 100%. 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 0.14.