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GCN Circular 12122

Subject
GRB 110709B: Swift detection of a burst
Date
2011-07-09T21:46:06Z (13 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@milkyway.gsfc.nasa.gov>
J. R. Cummings (NASA/UMBC), S. D. Barthelmy (GSFC),
D. N. Burrows (PSU), C. Gronwall (PSU),
S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU),
C. B. Markwardt (NASA/GSFC), D. M. Palmer (LANL), M. H. Siegel (PSU),
R. L. C. Starling (U Leicester) and C. A. Swenson (PSU) report on
behalf of the Swift Team:

At 21:32:39 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 110709B (trigger=456967).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 164.614, -23.484 which is 
   RA(J2000)  =  10h 58m 27s
   Dec(J2000) = -23d 29' 01"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows overlapping peaks
with a total duration of about 60 sec.  The peak count rate
was ~4200 counts/sec (15-350 keV), at ~30 sec after the trigger. 

The XRT began observing the field at 21:34:00.4 UT, 80.5 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 164.6552, -23.4550 which is equivalent to:
   RA(J2000)  = 10h 58m 37.24s
   Dec(J2000) = -23d 27' 17.9"
with an uncertainty of 5.3 arcseconds (radius, 90% containment). This
location is 171 arcseconds from the BAT onboard position, within the
BAT error circle. No event data are yet available to determine the
column density using X-ray spectroscopy. 

UVOT took a finding chart exposure of 150 seconds with the White
filter  starting 91 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 100% of  the XRT error circle. The typical
3-sigma upper limit has been about 19.6 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  0.05. 

Burst Advocate for this burst is J. R. Cummings (jayc 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.)
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