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GCN Circular 8526

Subject

GRB 081118: Swift-BAT refined analysis

Date

2008-11-19T00:07:42Z (15 years ago)

From

Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>

D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC),
E. A. Hoversten (PSU), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD),
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 081118 (trigger #334877)
(Hoversten, et al., GCN Circ. 8524Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 82.572, -43.305 deg, which is 
   RA(J2000)  =  05h 30m 17.3s 
   Dec(J2000) = -43d 18' 16.2" 
with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 61%.
 
The mask-weighted light curve shows a roughly symmetrical peak starting
at ~T+10 sec, peaking at ~T+25 sec, and ending at ~T+105 sec.
T90 (15-350 keV) is 67+- 28 sec (estimated error including systematics).
 
The time-averaged spectrum from T+19.6 to T+118.6 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.10 +- 0.16.  The fluence in the 15-150 keV band is 1.2 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+46.97 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/334877/BA/