GCN Circular 22815
Subject
GRB 180620A: Swift-BAT refined analysis
Date
2018-06-21T02:37:49Z (6 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
M. Stamatikos (OSU), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), P. A. Evans (U Leicester),
H. A. Krimm (NSF/USRA), 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 180620A (trigger #843122)
(Evans et al., GCN Circ. 22798). The BAT ground-calculated position is
RA, Dec = 279.890, 23.239 deg which is
RA(J2000) = 18h 39m 33.5s
Dec(J2000) = +23d 14' 18.6"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 42%.
The mask-weighted light curve shows a multi-peaked structure that starts
at ~T-7 s and ends at ~T+37 s. The two main peaks occur at ~T+5 s and ~T+12 s,
respectively. T90 (15-350 keV) is 23.16 +- 4.82 sec (estimated error including
systematics).
The time-averaged spectrum from T-6.92 to T+37.07 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.72 +- 0.05. The fluence in the 15-150 keV band is 5.8 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+4.47 sec in the 15-150 keV band
is 7.7 +- 0.4 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/843122/BA/