GCN Circular 9068
Subject
GRB 090401B: Swift-BAT refined analysis
Date
2009-04-01T12:38:51Z (15 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
M. Stamatikos (GSFC/ORAU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL),
A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS),
P. Schady (MSSL-UCL), J. Tueller (GSFC), T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
Using the data set from T-239 to T+914 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 090401B (trigger #348152)
(Schady, et al., GCN Circ. 9066). The BAT ground-calculated position is
RA, Dec = 95.095, -8.963 deg, which is
RA(J2000) = 06h 20m 22.7s
Dec(J2000) = -08d 57' 47.1"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 67%.
The mask-weighted light curve shows several FRED-like peaks with the first
starting at ~T-0.4 sec. The brightest peak is at ~T+7 sec with a long
exponential tail out to ~T+600 sec. T90 (15-350 keV) is 183 +- 39 sec
(estimated error including systematics).
The time-averaged spectrum from T-0.1 to T+326.1 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.37 +- 0.05. The fluence in the 15-150 keV band is 1.0 +- 0.0 x 10^-5 erg/cm2.
The 1-sec peak photon flux measured from T+6.49 sec in the 15-150 keV band
is 23.1 +- 0.5 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/348152/BA/