GCN Circular 43018

H. A. Krimm (NSF), S. D. Barthelmy (GSFC), R. Gupta (GSFC), S. Laha
(GSFC/UMBC), S. Lanava (PSU), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
M. J. Moss (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC), D. Sadaula
(GSFC/UMBC), T. Sakamoto (AGU) (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 251205A (trigger #1420873)
(Lanava et al., GCN Circ. 43005
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 ).  The BAT ground-calculated position is
RA, Dec = 200.260, 29.906 deg which is
   RA(J2000)  =  13h 21m 02.5s
   Dec(J2000) = +29d 54' 21.2"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment). The
partial coding was 45%.

The mask-weighted light curve shows a weak pulse that starts at ~T0 and
peaks at ~T+9 s. The main pulse ends at ~T+40s, followed by a weak tail
emission that lasts till ~T+140 s. T90 (15-350 keV) is 128.00 +- 65.97 sec
(estimated error including systematics).

The time-averaged spectrum from T+0.94 to T+144.94 sec is best fit by a
simple power-law model.  The power law index of the time-averaged spectrum
is 1.67 +- 0.27.  The fluence in the 15-150 keV band is 1.1 +- 0.2 x 10^-06
erg/cm2. The 1-sec peak photon flux measured from T+8.44 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/1420873