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GCN Circular 9364

Subject
GRB 090515: Swift-BAT refined analysis
Date
2009-05-15T12:44:58Z (15 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
A. P. Beardmore (U Leicester), 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), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC),
T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
 
Using the data sets from T-60 to T+243 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 090515 (trigger #352108)
(Beardmore, et al., GCN Circ. 9356).  The BAT ground-calculated position is
RA, Dec = 164.166, 14.469 deg, which is 
   RA(J2000)  =  10h 56m 39.8s 
   Dec(J2000) = +14d 28' 09.5" 
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 86%.
 
The mask-weighted light curve shows a single peak with a slightly longer
fall time than rise time. The total width is about 0.075 sec.
T90 (15-350 keV) is 0.036 +- 0.016 sec (estimated error including systematics).
 
The time-averaged spectrum from T+0.008 to T+0.056 sec is best fit by
a simple power-law model.  The power law index of the time-averaged
spectrum is 1.6 +- 0.2.  The fluence in the 15-150 keV band is
2.1 +- 0.4 x 10^-8 erg/cm2.  The 1-sec peak photon flux measured from
T-0.30 sec in the 15-150 keV band is 5.7 +- 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/352108/BA/
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