[vsnet-grb-info 19475] GRB 170604A: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21195
SUBJECT: GRB 170604A: Swift-BAT refined analysis
DATE:    17/06/05 02:19:40 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien at nasa.gov>

M. Stamatikos (OSU), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
K. L. Page (U Leicester), D. M. Palmer (LANL),
T. Sakamoto (AGU), 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 170604A (trigger #755867)
(Page et al., GCN Circ. 21191).  The BAT ground-calculated position is
RA, Dec = 342.645, -15.406 deg which is
  RA(J2000)  =  22h 50m 34.9s
  Dec(J2000) = -15d 24' 20.1"
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 8%.

The mask-weighted light curve shows several overlapping pulses that start
at ~ T-12 s and end at ~T+20 s. The main peak occurs at ~T+3 s.
T90 (15-350 keV) is 26.70 +- 6.21 sec (estimated error including systematics).

The time-averaged spectrum from T-11.66 to T+22.58 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.31 +- 0.12.  The fluence in the 15-150 keV band is 5.1 +- 0.4 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+2.66 sec in the 15-150 keV band
is 4.2 +- 0.9 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/755867/BA/