[vsnet-grb-info 16626] GRB 150607A: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17907
SUBJECT: GRB 150607A: Swift-BAT refined analysis
DATE:    15/06/07 22:51:34 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott at lheamail.gsfc.nasa.gov>

D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), V. D'Elia (ASDC), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
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 recent telemetry downlinks,
we report further analysis of BAT GRB 150607A (trigger #642620)
(D'Elia, et al., GCN Circ. 17904).  The BAT ground-calculated position is
RA, Dec = 140.015, 68.436 deg, which is 
   RA(J2000)  =  09h 20m 03.6s 
   Dec(J2000) = +68d 26' 10.3" 
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 31%.
 
The mask-weighted light curve shows multiple peaks starting at ~T-2 sec,
the brightest peak at ~T+8 sec, and ending at ~T+40 sec.
T90 (15-350 keV) is 26.3 +- 0.7 sec (estimated error including systematics).
 
The time-averaged spectrum from T-0.19 to T+27.58 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 0.99 +- 0.41, 
and Epeak of 84.9 +- 40.1 keV (chi squared 40.9 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 2.3 +- 0.2 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T+7.29 sec in the 15-150 keV band is
4.9 +- 0.5 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.59 +- 0.10 (chi squared 48.1 for 57 d.o.f.).  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/642620/BA/