GCN Circular 25097
Subject
GRB 190718A: Swift-BAT refined analysis
Date
2019-07-19T01:24:16Z (5 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), V. D'Elia (SSDC),
H. A. Krimm (NSF), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 190718A (trigger #915091)
(D'Elia et al., GCN Circ. 25082). The BAT ground-calculated position is
RA, Dec = 336.605, -41.184 deg which is
RA(J2000) = 22h 26m 25.2s
Dec(J2000) = -41d 11' 02.7"
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.
The mask-weighted light curve shows a main multi-peaked structure
that starts at ~ T0 and ends at ~T+17 s. In addition, there is a weak
pulse at ~T+700 s, which is at the same time as the large flare seen
by the XRT. T90 (15-350 keV) is 720.0 +- 35.8 sec (estimated error
including systematics).
The time-averaged spectrum from T+0.1 to T+17.1 sec (i.e., the duration
of the main emission) is best fit by a simple power-law model. The power
law
index of the time-averaged spectrum is 1.38 +- 0.26. The fluence in the
15-150 keV band is 3.6 +- 0.6 x 10^-7 erg/cm2. The spectral analysis for
the total burst duration from ~T0 to ~T+720 s does not produce reasonable
fits due to the large quiescent period from ~T+17 s to ~T+700 s.
The 1-sec peak photon flux measured from T+0.08 sec in the 15-150 keV band
is 1.0 +- 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/915091/BA/