GCN Circular 17628
Subject
GRB 150323A, Swift-BAT refined analysis
Date
2015-03-24T01:11:42Z (9 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
C. B. Markwardt (GSFC), A. Amaral-Rogers (U Leicester), 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),
D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU),
J. Tueller (GSFC), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-235 to T+967 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 150323A (trigger #635887)
(Amaral-Rogers, et al., GCN Circ. 17611). The BAT ground-calculated position is
RA, Dec = 128.173, 45.442 deg which is
RA(J2000) = 08h 32m 41.52s
Dec(J2000) = +45d 26' 29.76"
with an uncertainty of 2.07 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 32%.
The mask-weighted light curve shows a multi-peaked structure with two main
pulses. The first weaker pulse starts at ~ T0, peaks at ~ T+7 s, and ends at
~ T+25 s. The second brighter pulse starts at ~ T+125 s , peaks at ~ T+135 s,
and ends at ~ T+160 s. T90 (15-350 keV) is 149.6 +- 8.9 sec (estimated error
including systematics).
The time-averaged spectrum from T+2.6 to T+195.4 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.85 +- 0.07. The fluence in the 15-150 keV band is 6.1 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+135.64 sec in the 15-150 keV band
is 5.4 +- 0.3 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/635887/BA/