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GCN Circular 25534

Subject
GRB 190828B: Swift-BAT refined analysis
Date
2019-08-28T23:33:26Z (5 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
H. A. Krimm (NSF), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), S. Dichiara (NASA/GSFC/UMCP),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
(i.e. the Swift-BAT team):

Using the data set from T-239 to T+962 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 190828B (trigger #922808)
(Dichiara et al., GCN Circ. 25517Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 251.838, 27.287 deg which is
   RA(J2000)  =  16h 47m 21.2s
   Dec(J2000) = +27d 17' 12.9"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.

The mask-weighted light curve shows a multi-peak structure that starts
at ~T-40 s and ends at ~T+50 s. There are roughly three main peaks
that occurs at ~T0, ~T+11 s, and ~T+31 s, respectively.
T90 (15-350 keV) is 66.6 +- 6.2 sec (estimated error including systematics).

The time-averaged spectrum from T-42.4 to T+53.3 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.29 +- 0.07.  The fluence in the 15-150 keV band is 4.2 +- 0.2 x 10^-6
erg/cm2.
The 1-sec peak photon flux measured from T+10.74 sec in the 15-150 keV band
is 2.3 +- 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/922808/BA/