[vsnet-grb-info 15259] GRB 140709B: Swift detection of a burst

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16551
SUBJECT: GRB 140709B: Swift detection of a burst
DATE:    14/07/09 15:30:15 GMT
FROM:    Jamie A. Kennea at PSU/Swift-XRT  <kennea at swift.psu.edu>

C. A. Swenson (PSU), W. H. Baumgartner (GSFC/UMBC),
D. N. Burrows (PSU), S. B. Cenko (GSFC), M. M. Chester (PSU),
J. R. Cummings (NASA/UMBC), P. A. Evans (U Leicester),
N. Gehrels (NASA/GSFC), J. A. Kennea (PSU),
H. A. Krimm (CRESST/GSFC/USRA), V. Mangano (PSU),
F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester),
D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the
Swift Team:

At 15:15:45 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 140709B (trigger=603866).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 146.071, +63.505 which is 
   RA(J2000) = 09h 44m 17s
   Dec(J2000) = +63d 30' 20"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a multi-peaked
structure with a duration of about 150 sec.  The peak count rate
was ~1500 counts/sec (15-350 keV), at ~20 sec after the trigger. 

The XRT began observing the field at 15:17:15.9 UT, 91.0 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 146.05394, 63.53040 which
is equivalent to:
   RA(J2000)  = 09h 44m 12.95s
   Dec(J2000) = +63d 31' 49.4"
with an uncertainty of 3.9 arcseconds (radius, 90% containment). This
location is 95 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper. No
spectrum from the promptly downlinked event data is yet available to
determine the column density. 

The initial flux in the 2.5 s image was 3.60e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 250 seconds with the U filter starting 96
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 19.2 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 18.0 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.04. 

Burst Advocate for this burst is C. A. Swenson (cswenson 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.)