TITLE:   GCN CIRCULAR
NUMBER:  16503
SUBJECT: GRB 140703A: Swift detection of a burst
DATE:    14/07/03 00:52:07 GMT
FROM:    Jamie A. Kennea at PSU/Swift-XRT  <kennea@swift.psu.edu>

D. Kocevski (NASA/GSFC/ORAU), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (NASA/UMBC), J. A. Kennea (PSU),
N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester), J. L. Racusin (NASA/GSFC),
M. H. Siegel (PSU) and T. N. Ukwatta (MSU) report on behalf of the
Swift Team:

At 00:37:17 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 140703A (trigger=603243).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 12.990, +45.095 which is 
   RA(J2000) = 00h 51m 58s
   Dec(J2000) = +45d 05' 41"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a two-peak
structure with a duration of about 90 sec.  The peak count rate
was ~1781 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 00:39:09.8 UT, 112.8 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 12.9958, 45.1015 which is equivalent to:
   RA(J2000)  = +00h 51m 58.99s
   Dec(J2000) = +45d 06' 05.4"
with an uncertainty of 4.7 arcseconds (radius, 90% containment). This
location is 27 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. 

The initial flux in the 2.5 s image was 1.12e-08 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 116 seconds with the White filter
starting 123 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 none of
the XRT error circle. 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 0.10. 

Burst Advocate for this burst is D. Kocevski (dankocevski AT gmail.com). 
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.)