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GCN Circular 23489

Subject

GRB 181202A: Swift-BAT refined analysis

Date

2018-12-02T23:49:59Z (6 years ago)

From

Amy Lien at GSFC <amy.y.lien@nasa.gov>

T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),
J. K. Cannizzo (NASA/UMBC), 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)
(i.e. the Swift-BAT team):

Using the data set from T-240 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 181202A (trigger #874334)
(Cannizzo et al., GCN Circ. 23482Loading...
 
 ).  The BAT ground-calculated position is
RA, Dec = 280.737, 27.976 deg which is
  RA(J2000)  =  18h 42m 56.9s
  Dec(J2000) = +27d 58' 33.4"
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 96%.

The mask-weighted light curve shows a double-peaked structure that starts
at ~T0 and ends at ~T+7 s. The two peaks occur at ~T+1 s and ~T+6 s, respectively.
T90 (15-350 keV) is 6.56 +- 0.61 sec (estimated error including systematics).

The time-averaged spectrum from T-0.26 to T+6.76 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.61 +- 0.24.  The fluence in the 15-150 keV band is 2.5 +- 0.4 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.69 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/874334/BA/