[vsnet-grb-info 16394] GRB 150403A: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17675
SUBJECT: GRB 150403A: Swift-BAT refined analysis
DATE:    15/04/04 18:40:14 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien at nasa.gov>

T. Sakamoto (AGU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
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 150403A (trigger #637044)
(Lien, et al., GCN Circ. 17665).  The BAT ground-calculated position is
RA, Dec = 311.505, -62.706 deg which is
  RA(J2000)  =  20h 46m 01.1s
  Dec(J2000) = -62d 42' 20.5"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 40%.

The mask-weighted light curve shows a single bright peak. The main structure
starts at ~ T-10 s, peaks at ~ T+6 s, and ends at ~ T+35 s. There are some
weaker emissions that starts at ~ T-170 s and lasts till ~ T+195 s. T90 (15-350 keV)
is 40.90 +- 11.72 sec (estimated error including systematics).

The time-averaged spectrum from T-83.15 to T+145.37 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.23 +- 0.04.  The fluence in the 15-150 keV band is 1.7 +- 0.03 x 10^-5 erg/cm2.
The 1-sec peak photon flux measured from T+5.80 sec in the 15-150 keV band
is 17.6 +- 0.6 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/637044/BA/