GCN Circular 32854

A. Y. Lien (U Tampa), S. D. Barthelmy (GSFC), R. Brivio (INAF-OAB),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU),
M. Stamatikos (OSU) (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 221024A (trigger #1131029)
(Brivio, et al., GCN Circ. 32827
Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 169.702, 33.068 deg which is
   RA(J2000)  =  11h 18m 48.6s
   Dec(J2000) = +33d 04' 04.9"
with an uncertainty of 2.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 35%.

The mask-weighted light curve shows a rather weak pulse starting at the trigger
time, peaking around T+5 seconds and decaying to baseline by about T+40 seconds.
There is some low-level emission following this peak, including a possible peak
In the low-energy bands at approximately T+200 seconds. The pipeline-calculated
T90 (15-350 keV) is 120+-111 sec (estimated error including systematics), with the
large stated error due to uncertainty in whether the possible T+200 peak contains
at least 5% of the burst fluence.

The time-averaged spectrum from T+0.00 to T+221.28 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.39 +- 0.25.  The fluence in the 15-150 keV band is 1.5 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+2.93 sec in the 15-150 keV band
is 1.5 +- 0.3 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/1131029/BA/