[vsnet-grb-info 19672] GRB 170804A: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21416
SUBJECT: GRB 170804A: Swift-BAT refined analysis
DATE:    17/08/05 15:45:14 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien at nasa.gov>

H. A. Krimm (NSF/USRA), S. D. Barthelmy (GSFC),
A. Cholden-Brown (PSU), J. R. Cummings (CPI),
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+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 170804A (trigger #766194)
(Cholden-Brown et al., GCN Circ. 21410).  The BAT ground-calculated position is
RA, Dec = 6.404, -64.781 deg which is
  RA(J2000)  =  00h 25m 37.0s
  Dec(J2000) = -64d 46' 50.9"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 75%.

The mask-weighted light curve shows several over-lapping pulses that
start at ~T0 and end at ~T+60 s. T90 (15-350 keV) is 43.4 +- 9.8 sec
(estimated error including systematics).

The time-averaged spectrum from T+1.98 to T+60.90 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.67 +- 0.13.  The fluence in the 15-150 keV band is 1.3 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+25.10 sec in the 15-150 keV band
is 0.9 +- 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/766194/BA/