[vsnet-grb-info 20717] GRB 180620A: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22815
SUBJECT: GRB 180620A: Swift-BAT refined analysis
DATE:    18/06/21 02:37:49 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien at 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/