[vsnet-grb-info 11659] GRB 120312A: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  13052
SUBJECT: GRB 120312A: Swift-BAT refined analysis
DATE:    12/03/12 22:24:54 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), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
 
Using the data set from T-240 to T+736 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 120312A (trigger #517566)
(Stamatikos, et al., GCN Circ. 13049).  The BAT ground-calculated position is
RA, Dec = 251.812, 23.881 deg, which is 
   RA(J2000)  =  16h 47m 14.8s 
   Dec(J2000) = +23d 52' 50.3" 
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 35%.
 
The mask-weighted light curve shows a single slightly symmetric peak
starting at ~T-10 sec, peaking at ~T+0.5 sec, and ending at ~T+35 sec.
T90 (15-350 keV) is 14.2 +- 3.4 sec (estimated error including systematics).
 
The time-averaged spectrum from T-1.42 to T+15.87 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.72 +- 0.23.  The fluence in the 15-150 keV band is 5.7 +- 0.8 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.95 sec in the 15-150 keV band
is 1.3 +- 0.3 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/517566/BA/