GCN 43507: GRB 260122B: Swift-BAT refined analysis

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

Using the data set from T-60 to T+243 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 260122B (trigger #1443066)
(Mei et al., GCN Circ. 43502).  The ground analysis confirms that this
event is indeed a GRB and not due to background fluctuations (Mei et al.,
GCN Circ. 43502). The BAT ground-calculated position is
RA, Dec = 336.096, -59.176 deg which is
   RA(J2000)  =  22h 24m 22.9s
   Dec(J2000) = -59d 10' 32.1"
with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 57%.

The mask-weighted light curve shows a single-pulse structure that starts
~T-1 s, peaks at ~T+9 s, and ends at ~T+20 s. T90 (15-350 keV) is 16.59 +-
3.89 sec (estimated error including systematics).

The time-averaged spectrum from T+0.23 to T+19.51 sec is best fit by a
simple power-law model.  The power law index of the time-averaged spectrum
is 1.34 +- 0.17.  The fluence in the 15-150 keV band is 1.0 +- 0.1 x 10^-06
erg/cm2. The 1-sec peak photon flux measured from T+8.46 sec in the 15-150
keV band is 1.6 +- 0.3 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/1443066