GCN Circular 8709

E. E. Fenimore (LANL), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), D. Grupe (PSU), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD), D. M. Palmer (LANL),
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-119 to T+183 sec from the recent telemetry 
downlink,
we report further analysis of BAT GRB 081222 (trigger #337914)
(Grupe, et al., GCN Circ. 8691
Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 22.748, -34.095 deg which is
  RA(J2000)  =  01h 30m 59.5s
  Dec(J2000) = -34d 05' 41.4"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The burst was in the fully-coded field of view.

The mask-weighted light curve shows a main peak with several subpeaks
from about T+0 to T+20 sec and an exponential tail visible to about
T+70 sec.  T90 (15-350 keV) is 24 +- 3 sec (estimated error including
systematics).

The time-averaged spectrum from T-0.6 to T+38.0 sec is best fit by a 
power law
with an exponential cutoff.  This fit gives a photon index 1.08 +- 0.15,
and Epeak of 131 +- 31 keV (chi squared 45.61 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 4.8 +- 0.1 x 10^-06 
erg/cm2
and the 1-sec peak flux measured from T+3.45 sec in the 15-150 keV band is
7.7 +- 0.2 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.48 +- 0.03 (chi squared 68.25 for 57 d.o.f.).  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/337914/BA/