[vsnet-grb-info 5256] GRB 071020: Swift detection of a bright burst

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6949
SUBJECT: GRB 071020: Swift detection of a bright burst
DATE:    07/10/20 07:18:57 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott at lheamail.gsfc.nasa.gov>

S. T. Holland (CRESST/USRA/GSFC), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester),
P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC),
C. Guidorzi (Univ Bicocca&INAF-OAB), C. Pagani (PSU),
K. L. Page (U Leicester), D. M. Palmer (LANL), A. M. Parsons (GSFC),
T. Sakamoto (NASA/UMBC), R. L. C. Starling (U Leicester) and
T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team:

At 07:02:26 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 071020 (trigger=294835).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 119.664, +32.861 which is 
   RA(J2000)  =  07h 58m 39s
   Dec(J2000) = +32d 51' 40"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a double peak
structure with a duration of about 5 sec.  The peak count rate
was ~22000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 07:03:28 UT, 61 seconds after the
BAT trigger. In 268 s of promptly downlinked data XRT found a bright, fading,
uncatalogued X-ray source located at RA, Dec 119.6656, 32.8611 which is
   RA(J2000)  = 07 58 39.74
   Dec(J2000) = +32 51 40.0
with an uncertainty of 4.3 arcsec (radius, 90% containment). 
This location is 5 arcseconds from the BAT on-board position,
within the BAT error circle. The initial flux in the 2.5s image
was 1.8e-09 erg/cm2/s (0.2-10 keV). 

There will be no UVOT data products for this burst, because it is still in
engineering mode after the recent recovery to the new 3-gyro mode. 

Burst Advocate for this burst is S. T. Holland (sholland AT milkyway.gsfc.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.)