[vsnet-grb-info 11829] GRB 120404A: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  13220
SUBJECT: GRB 120404A: Swift-BAT refined analysis
DATE:    12/04/05 00:40:32 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott at lheamail.gsfc.nasa.gov>

T. N. Ukwatta (MSU), 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),
G. Stratta (ASDC), J. Tueller (GSFC)
(i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 120404A (trigger #519380)
(Strata, et al., GCN Circ. 13208).  The BAT ground-calculated position is
RA, Dec = 235.002, 12.883 deg, which is 
   RA(J2000)  =  15h 40m 00.4s 
   Dec(J2000) = +12d 52' 57.3" 
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 49%.
 
The mask-weighted light curve shows several overlapping peaks starting
at ~T-20 sec, peaking at ~T+4 sec, and ending at ~T+80 sec.
T90 (15-350 keV) is 38.7 +- 4.1 sec (estimated error including systematics).
 
The time-averaged spectrum from T-7.31 to T+38.45 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.85 +- 0.13.  The fluence in the 15-150 keV band is 1.6 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+3.29 sec in the 15-150 keV band
is 1.2 +- 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/519380/BA/