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GCN Circular 25860

Subject
GRB 190926A: Swift-BAT refined analysis
Date
2019-09-28T20:05:29Z (5 years ago)
From
Hans Krimm at NSF/NASA-GSFC <hkrimm@nsf.gov>
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), J. R. Cummings (CPI),
H. A. Krimm (NSF), A. Y. Lien (GSFC/UMBC), A. Melandri (INAF-OAB),
D. M. Palmer (LANL), 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 190926*A (trigger #926515)
(Melandri, et al., GCN Circ. 25848).  The BAT ground-calculated position is
RA, Dec = 100.616, 59.531 deg which is 
  RA(J2000)  =  06h 42m 27.9s 
  Dec(J2000) = +59d 31' 51.2" 
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 50%.

The BAT mask-weighted light curve shows a complex structure with multiple
peaks extending from roughly T-120 sec to T+450 sec.  T90 (15-350 keV) is 
368.9 +- 20.9 sec (estimated error including systematics).

The time-averaged spectrum from T-0.00 to T+395.46 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.14 +- 0.18.  The fluence in the 15-150 keV band is 2.5 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+52.95 sec in the 15-150 keV band
is 0.6 +- 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/926515/BA/
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