TITLE:   GCN CIRCULAR
NUMBER:  18452
SUBJECT: GRB 151022A: Swift-BAT refined analysis
DATE:    15/10/23 17:34:15 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

A. Y. Lien (GSFC/UMBC),S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC),
P. D'Avanzo (INAF-OAB), N. Gehrels (GSFC),H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)(i.e. the Swift-BAT team):

Using the data set from T-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 151022A (trigger #661036)
(D'Avanzo, et al., GCN Circ. 18436).  The BAT ground-calculated position is
RA, Dec = 349.223, 55.812 deg which is
  RA(J2000)  =  23h 16m 53.5s
  Dec(J2000) = +55d 48' 43.4"
with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 35%.

The mask-weighted light curve shows a single FRED-like peak, with some
superimposed structure, peaking near the trigger time and fading to near
background by ~200 seconds. T90 (15-350 keV) is 116.7 +/- 23.0 sec
(estimated error including systematics).

The time-averaged spectrum from T-1.5 to T+132.8 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.98 +- 0.29.  The fluence in the 15-150 keV band is 1.1 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+10.37 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/661036/BA/