TITLE:   GCN CIRCULAR
NUMBER:  25930
SUBJECT: GRB 191001B: Swift-BAT refined analysis
DATE:    19/10/02 23:53:19 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), T. Sakamoto (AGU),
M. Stamatikos (OSU), E. Troja (NASA/GSFC/UMCP),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):

Using the data set from T-239 to T+962 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 191001B (trigger #927345)
(Troja et al., GCN Circ. 25902).  The BAT ground-calculated position is
RA, Dec = 86.423, -15.880 deg which is
   RA(J2000)  =  05h 45m 41.5s
   Dec(J2000) = -15d 52' 48.3"
with an uncertainty of 3.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 33%.

The mask-weighted light curve shows a multi-peaked structure that starts
at ~T-10 s and ends at ~T+130 s. T90 (15-350 keV) is 108.9 +- 15.1 sec
(estimated error including systematics).

The time-averaged spectrum from T-8.77 to T+126.11 sec is best fit by a
simple
power-law model.  The power law index of the time-averaged spectrum is
1.58 +- 0.11.  The fluence in the 15-150 keV band is 4.6 +- 0.3 x 10^-6
erg/cm2.
The 1-sec peak photon flux measured from T+20.44 sec in the 15-150 keV band
is 1.8 +- 0.4 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/927345/BA/