TITLE:   GCN CIRCULAR
NUMBER:  6748
SUBJECT: GRB 070810A: Swift-BAT refined analysis
DATE:    07/08/10 19:13:07 GMT
FROM:    Jay R. Cummings at NASA/GSFC/Swift  <jayc@milkyway.gsfc.nasa.gov>

C. Markwardt (GSFC/UMD), L. Barbier (GSFC), S. D. Barthelmy (GSFC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), 
H. Krimm (GSFC/USRA), D. Palmer (LANL), A. Parsons (GSFC),
T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU),
J. Tueller (GSFC), T. Ukwatta (GWU)
 
Using the data set from T-240 to T+804 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 070810A (trigger #287364) (Cummings, 
et al., GCN Circ. 6733).  The BAT ground-calculated position is
RA, Dec = 189.947, 10.747 deg which is 
   RA(J2000) = 12h 39m 47.2s 
   Dec(J2000) = 10d 44' 48" 
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment). This
is 1.0 arcmin from the optical and refined XRT positions (Chester et al. 
GCN circ. 6735 and Evans et al. GCN circ. 6736). The partial coding was 53%.
 
The mask-weighted light curve shows a single peak with softening spectral
evolution. T90 (15-350 keV) is 11.0 +- 1 sec (estimated error including 
systematics).
 
The time-averaged spectrum from T-3.1 to T+14.3 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.04 +- 0.14. The fluence in the 15-150 keV band is 
6.9 +- 0.6 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from 
T-0.11 sec in the 15-150 keV band is 1.9 +- 0.2 ph/cm2/sec.  All the quoted 
errors are at the 90% confidence level.