GCN Circular 10265
Subject
GRB 091208B, Swift-BAT refined analysis
Date
2009-12-08T15:59:30Z (14 years ago)
From
Jay R. Cummings at NASA/GSFC/Swift <james.r.cummings@nasa.gov>
W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC),
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), C. Pagani (PSU), 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-60 to T+243 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 091208B (trigger
#378559) (Pagani, et al., GCN Circ. 10256). The BAT ground-
calculated position is RA, Dec = 29.411, 16.881 deg which is
RA(J2000) = 01h 57m 38.5s
Dec(J2000) = +16d 52' 50.7"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 10%.
The mask-weighted light curve shows two separated FRED peaks. The first
at T0 was weaker and softer than the second at T+8 sec.
T90 (15-350 keV) is 14.9 +- 3.7 sec (estimated error including
systematics).
The time-averaged spectrum from T-0.2 to T+22.3 sec is best fit by a
simple power-law model. The power law index of the time-averaged
spectrum is 1.74 +- 0.11. The fluence in the 15-150 keV band was
3.3 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from
T+8.1 sec in the 15-150 keV band was 15.2 +- 1.0 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/378559/BA/