GCN Circular 9799
Subject
GRB 090814A: Swift-BAT refined analysis
Date
2009-08-14T12:55:19Z (15 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), A. M. Parsons (GSFC),
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 set from T-239 to T+963 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 090814A (trigger #359951)
(Ukwatta, et al., GCN Circ. 9793). The BAT ground-calculated position is
RA, Dec = 239.613, 25.586 deg which is
RA(J2000) = 15h 58m 27.2s
Dec(J2000) = +25d 35' 09.0"
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 37%.
The mask-weighted light curve shows a few semi-overlapping peaks starting
at ~T-18 sec, peaking at ~T-13 sec, peaking at ~T+8 sec, and ending
at ~T+115 sec. There is possible 10-sec precursor peak (3 sigma) at ~T-145 sec.
T90 (15-350 keV) is 80 +- 8 sec (estimated error including systematics).
The time-averaged spectrum from T-16.4 to T+73.6 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.81 +- 0.19. The fluence in the 15-150 keV band is 1.3 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T-12.68 sec in the 15-150 keV band
is 0.6 +- 0.2 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/359951/BA/