[AAVSO-HEN] GRB 081211: Swift-BAT refined analysis

[grb at aavso.org]

The following is a GCN Circular circulated via the AAVSO network.
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TITLE:   GCN CIRCULAR
NUMBER:  8658
SUBJECT: GRB 081211: Swift-BAT refined analysis
DATE:    08/12/11 22:42:23 GMT
FROM:    Hans Krimm at NASA-GSFC  <hans.a.krimm at nasa.gov>

Using the data set from T-239 to T+963 sec from the recent telemetry 
downlink,
we report further analysis of BAT GRB 081211 (trigger #337115)
(Krimm, et al., GCN Circ. 8653).  The BAT ground-calculated position is
RA, Dec = 328.082, -33.818 deg which is
   RA(J2000)  =  21h 52m 19.7s
   Dec(J2000) = -33d 49' 05.9"
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 42%.
 
The mask-weighted light curve shows a single weak peak extending in time
from T-1 to T+3 seconds. There is a possible precursor at ~T-180 sec.
T90 (15-350 keV) is 3.5 +- 0.9 sec (estimated error including systematics).
 
The time-averaged spectrum from T-1.1 to T+2.7 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.34 +- 0.41.  The fluence in the 15-150 keV band is 1.3 +- 0.3 x 10^-7 
erg/cm2.
The 1-sec peak photon flux measured from T+0.19 sec in the 15-150 keV band
is 0.8 +- 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/337115/BA/