GCN Circular 21678
Subject
GRB 170823A: Swift-BAT refined analysis
Date
2017-08-24T15:35:39Z (7 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
M. Stamatikos (OSU), 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),
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 170823A (trigger #769177)
(Troja et al., GCN Circ. 21666). The BAT ground-calculated position is
RA, Dec = 188.713, 35.549 deg which is
RA(J2000) = 12h 34m 51.1s
Dec(J2000) = +35d 32' 58.0"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 79%.
The mask-weighted light curve shows a multi-peaked light curve that starts at
~ T0 and ends at ~T+90 s. T90 (15-350 keV) is 69.4 +- 11.7 sec (estimated error
including systematics).
The time-averaged spectrum from T-0.36 to T+87.31 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
2.06 +- 0.09. The fluence in the 15-150 keV band is 2.6 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+21.40 sec in the 15-150 keV band
is 3.7 +- 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/769177/BA/