[vsnet-grb-info 24176] GRB 191122A: Swift-BAT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  26275
SUBJECT: GRB 191122A: Swift-BAT refined analysis
DATE:    19/11/22 23:46:51 GMT
FROM:    Hans Krimm at NSF/NASA-GSFC  <hkrimm at nsf.gov>

H. A. Krimm (NSF), S. D. Barthelmy (GSFC),  S. Laha (GSFC/UMBC),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), B. Sbarufatti (PSU), 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 191122A (trigger #938899)
(Sbarufatti, et al., GCN Circ. 26269).  The BAT ground-calculated position is
RA, Dec = 54.290, -32.176 deg which is 
   RA(J2000)  =  03h 37m 09.7s 
   Dec(J2000) = -32d 10' 35.4" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 26%.

The mask-weighted light curve shows a single FRED-shaped pulse rising from 
T-20 sec to T+0 sec, then decaying out to roughly T+250 sec.
T90 (15-350 keV) is 153.3 +- 38.3 sec (estimated error including systematics).

The time-averaged spectrum from -11.2 to 245.4 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 1.24 +- 0.28, 
and Epeak of 89.2 +- 41.9 keV (chi squared 69.11 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 6.6 +- 0.3 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T+6.44 sec in the 15-150 keV band is
3.1 +- 0.4 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.67 +- 0.07 (chi squared 76.48 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/938899/BA/