[vsnet-grb-info 8127] GRB 090712: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9660
SUBJECT: GRB 090712: Swift-BAT refined analysis
DATE:    09/07/12 16:08:32 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott at lheamail.gsfc.nasa.gov>

S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), S. T. Holland (CRESST/USRA/GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL),
A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS),
M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+355 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 090712 (trigger #357072)
(Holland, et al., GCN Circ. 9659).  The BAT ground-calculated position is
RA, Dec = 70.097, 22.525 deg, which is 
   RA(J2000)  =  04h 40m 23.2s 
   Dec(J2000) = +22d 31' 29.4" 
with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 67%.
 
The mask-weighted light curve shows a mostly smooth peak starting
at ~T-160 sec, peaking at ~T_zero, and ending at ~T+170 sec.
T90 (15-350 keV) is 145 +- 52 sec (estimated error including systematics).
 
The time-averaged spectrum from T-99.1 to T+157.8 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.33 +- 0.11.  The fluence in the 15-150 keV band is 4.0 +- 0.3 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T-6.10 sec in the 15-150 keV band
is 0.9 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level. 
 
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/357072/BA/