[vsnet-grb-info 12708] GRB 121211A: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14067
SUBJECT: GRB 121211A: Swift-BAT refined analysis
DATE:    12/12/12 13:36:02 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), V. Mangano (INAF-IASFPA), D. M. Palmer (LANL),
T. Sakamoto (AGU), 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+962 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 121211A (trigger #541200)
(Mongano, et al., GCN Circ. 14057).  The BAT ground-calculated position is
RA, Dec = 195.575, 30.173 deg, which is 
   RA(J2000)  =  13h 02m 18.0s 
   Dec(J2000) = +30d 10' 24.4" 
with an uncertainty of 4.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 23%.
 
The mask-weighted light curve shows a peak starting at ~T-5 sec, peaking at
~T+2 sec, and returning to baseline at ~T+5 sec. Then a second set of peaks
starts at ~T+20 with the main emission from T+105 to ~T+200 sec.
T90 (15-350 keV) is 182 +- 39 sec (estimated error including systematics).
 
The time-averaged spectrum from T-0.48 to T+196.77 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.36 +- 0.26.  The fluence in the 15-150 keV band is 1.3 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+1.07 sec in the 15-150 keV band
is 1.0 +- 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/541200/BA/