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GCN Circular 6986

Subject
GRB 071025: Swift detection of a burst
Date
2007-10-25T04:30:05Z (16 years ago)
From
Claudio Pagani at PSU/Swift-XRT <pagani@astro.psu.edu>
C. Pagani (PSU), W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU),
J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC),
C. Gronwall (PSU), C. B. Markwardt (CRESST/GSFC/UMD),
F. E. Marshall (NASA/GSFC), J. L. Racusin (PSU),
T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU) report on behalf of the
Swift Team:

At 04:08:54 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 071025 (trigger=295301).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 355.084, +31.757 which is 
   RA(J2000)  =  23h 40m 20s
   Dec(J2000) = +31d 45' 24"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  Although this is a 64 sec image trigger, 
the light curve appears to have a single broad peak with duration 
about 120 sec near time T+100, with peak count rate 2000 ct/s. 

The XRT began observing the field at 04:11:19 UT, 146 seconds after the
BAT trigger. XRT found a bright, fading, uncatalogued X-ray source
located at RA, Dec 355.0765, +31.7776 which is
   RA(J2000)  =  23h 40m 18.3s
   Dec(J2000) =  31d 46' 39.3"
with an uncertainty of 6.8 arcseconds (radius, 90% containment). 
This location is 78 arcseconds from the BAT on-board position,
within the BAT error circle. The initial flux in the 0.1s image
was 9.1e-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 155 seconds after the BAT trigger. No 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 18.5 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
0.08. 

Burst Advocate for this burst is C. Pagani (pagani AT astro.psu.edu). 
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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