GCN Circular 12476

H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), S. Immler (CRESST/GSFC/UMD),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC),
M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU)
(i.e. the Swift-BAT team):
 
Using the data set from T-60 to T+243 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 111022A (trigger #506070)
(Immler, et al., GCN Circ. 12471
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 ).  The BAT ground-calculated position is
RA, Dec = 275.871, -23.666 deg, which is 
   RA(J2000)  =  18h 23m 29.1s 
   Dec(J2000) = -23d 39' 58.7" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 66%.
 
The mask-weighted light curve shows two peaks: a small peak starting
at ~T-18 sec, peaking at ~T-12 sec, merging into the main peak
at ~T-8 sec, peaking at ~T-2 sec, and ending at ~T+15 sec.
T90 (15-350 keV) is 24.7 +- 3.6 sec (estimated error including systematics).
 
The time-averaged spectrum from T-17.69 to T+18.57 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 1.01 +- 0.37, 
and Epeak of 64.7 +- 13.9 keV (chi squared 63.3 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 2.0 +- 0.1 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T-1.46 sec in the 15-150 keV band is
2.5 +- 0.2 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.73 +- 0.08 (chi squared 76.5 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/506070/BA/