GCN Circular 8507
Subject
GRB 081109A, Swift-BAT refined analysis
Date
2008-11-09T16:42:12Z (16 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
C. B. Markwardt (GSFC/UMD), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
S. Immler (CRESST/GSFC/UMD), H. A. Krimm (GSFC/USRA), D. M. Palmer (LANL),
T. Sakamoto (GSFC/UMBC), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC),
T. N. Ukwatta (GWU)
(i.e. the Swift-BAT team):
Using the data set from T-240 to T+962 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 081109A (trigger #334112)
(Immler, et al., GCN Circ. 8500). The BAT ground-calculated position is
RA, Dec = 330.798, -54.711 deg, which is
RA(J2000) = 22h 03m 11.5s
Dec(J2000) = -54d 42' 40.5"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 73%.
The mask-weighted light curve shows a smooth rise to a single peak
starting at ~T-90 sec, peaking at ~T+5 sec, and roughly exponentially decaying
back to baseline at ~T+400 sec.
T90 (15-350 keV) is 190 +- 60 sec (estimated error including systematics).
The time-averaged spectrum from T-15.9 to T+416.1 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.72 +- 0.09. The fluence in the 15-150 keV band is 3.6 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+7.64 sec in the 15-150 keV band
is 1.1 +- 0.0 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/334112/BA/