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GCN Circular 21458

Subject

GRB 170810A: Swift-BAT refined analysis

Date

2017-08-11T15:26:06Z (7 years ago)

From

Takanori Sakamoto at AGU <tsakamoto@phys.aoyama.ac.jp>

C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), J. R. Cummings (CPI),
S. L. Gibson (U Leicester), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), 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-240 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 170810A (trigger #767284)
(Gibson, et al., GCN Circ. 21450Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 187.928, 3.664 deg which is
    RA(J2000)  =  12h 31m 42.8s
    Dec(J2000) = +03d 39' 49.8"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 93%.

The mask-weighted light curve shows a complex multi-peaked structure that
starts at ~T-20 s and ends at ~T+180 s.  The brightest peak occurs at ~T+0.5 s.
T90 (15-350 keV) is 152.4 +- 21.5 sec (estimated error including systematics).
  
The time-averaged spectrum from T-24.33 to T+157.74 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.24 +- 0.07.  The fluence in the 15-150 keV band is 4.8 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+0.15 sec in the 15-150 keV band
is 1.2 +- 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/767284/BA/