GCN Circular 42444

T. Sakamoto (AGU), S. D. Barthelmy (GSFC), R. Gupta (GSFC), H. A. Krimm
(NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
M. J. Moss (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC), D. Sadaula
(GSFC/UMBC) (i.e. the Swift-BAT team):

Using the data set from T-240 to T+613 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 251024A (trigger #1406589)
(Moss et al., GCN Circ. 42426
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 ).  The BAT ground-calculated position is
RA, Dec = 306.666, -68.576 deg which is
   RA(J2000)  =  20h 26m 39.7s
   Dec(J2000) = -68d 34' 34.3"
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 84%.

The mask-weighted light curve shows a weak pulse structure that starts at
~T+1 s and peaks at ~T+3 s. The main pulse structure ends at ~T+25 s, and
there are some tail emissions that last till ~T+100 s. T90 (15-350 keV) is
82.66 +- 23.27 sec (estimated error including systematics).

The time-averaged spectrum from T+1.16 to T+97.28 sec is best fit by a
simple power-law model.  The power law index of the time-averaged spectrum
is 1.68 +- 0.30.  The fluence in the 15-150 keV band is 6.5 +- 1.2 x 10^-07
erg/cm2. The 1-sec peak photon flux measured from T+2.16 sec in the 15-150
keV band is 0.5 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90%
confidence level.

The results of the batgrbproduct analysis are available at
https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1406589