GRB 081008, Swift-BAT refined analysis
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), H. A. Krimm (GSFC/USRA), C. B. Markwardt
(GSFC/UMD), K. McLean (GSFC/UMD), A. M. Parsons (GSFC), J. L. Racusin
(PSU), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos
(GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU); (i.e. the
Using the data set from T-240 to T+963 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 081008 (trigger
#331093) (Racusin et al., GCN Circ. 8344). The BAT ground-calculated
position is RA, Dec = 279.968, -57.433 deg which is
RA(J2000) = 18h 39m 52.4s
Dec(J2000) = -57d 25' 58.8"
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90%
containment). The partial coding was 81%.
The mask-weighted lightcurve shows two strong peaks at T+0 and T+110s.
T90 (15-350 keV) is 185.5 +- 40.3 sec (estimated error including
The time-averaged spectrum from T-65 to T+201 sec is best fit by a
simple power-law model. A cutoff-power law model is also an
acceptable fit with an E_peak of 88 keV. The power law index of the
time-averaged spectrum is 1.69 +- 0.07. The fluence in the 15-150 keV
band is 4.3 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux
measured from T+7.52 sec in the 15-150 keV band is 1.3 +- 0.1
ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at