GCN Circular 25211
Subject
GRB 190727B: Swift-BAT refined analysis
Date
2019-07-28T23:21:40Z (5 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),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
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 190727B (trigger #916733)
(Lien et al., GCN Circ. 25176). The BAT ground-calculated position is
RA, Dec = 126.500, -13.272 deg which is
RA(J2000) = 08h 25m 59.9s
Dec(J2000) = -13d 16' 18.9"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 70%.
The mask-weighted light curve shows a structure with multiple bright pulses
that starts at ~T-20 s and ends at ~T+45 s. The brightest peak occurs at
~T+2 s. T90 (15-350 keV) is 40.14 +- 1.40 sec (estimated error including
systematics).
The time-averaged spectrum from T-21.30 to T+44.47 sec is best fit by a
simple
power-law model. The power law index of the time-averaged spectrum is
1.41 +- 0.03. The fluence in the 15-150 keV band is 1.8 +- 0.03 x 10^-5
erg/cm2.
The 1-sec peak photon flux measured from T+1.13 sec in the 15-150 keV band
is 20.9 +- 0.7 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/916733/BA/