[vsnet-grb-info 21401] GRB 181203A: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23500
SUBJECT: GRB 181203A: Swift-BAT refined analysis
DATE:    18/12/04 03:52:49 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien at nasa.gov>

S. D. Barthelmy (GSFC), J. R. Cummings (CPI),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU),
E. Troja (NASA/GSFC/UMCP), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):

Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 181203A (trigger #874475)
(Troja et al., GCN Circ. 23493).  The BAT ground-calculated position is
RA, Dec = 108.341, -39.783 deg which is
   RA(J2000)  =  07h 13m 21.8s
   Dec(J2000) = -39d 46' 57.1"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 83%.

The mask-weighted light curve shows a single-peaked structure that starts at
~T-2 s, peaks at ~T+1 s, and ends at ~T+16 s. T90 (15-350 keV) is 15.30 +- 1.75 sec
(estimated error including systematics).

The time-averaged spectrum from T-1.96 to T+15.77 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.79 +- 0.15.  The fluence in the 15-150 keV band is 7.8 +- 0.7 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+1.02 sec in the 15-150 keV band
is 1.1 +- 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/874475/BA/