GCN Circular 45918

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), T.
Sakamoto (AGU) (i.e. the Swift-BAT team):

Using the data set from T-120 to T+662 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 261010A (trigger #1516528)
(Lien et al., GCN Circ. 45889
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 ).  The BAT ground-calculated position is
RA, Dec = 248.767, 26.600 deg which is
   RA(J2000)  =  16h 35m 04.2s
   Dec(J2000) = +26d 36' 01.3"
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment). The
partial coding was 83%.

The mask-weighted light curve shows a main pulse that starts and peaks at
~T0 and ends at ~T+3 s. In addition, there are some weak emission that
starts prior to the main pulse at ~T-10 s and lasts till ~T+70 s. T90
(15-350 keV) is 71.50 +- 14.07 sec (estimated error including systematics).

The time-averaged spectrum from T-9.28 to T+76.45 sec is best fit by a
simple power-law model.  The power law index of the time-averaged spectrum
is 1.43 +- 0.17.  The fluence in the 15-150 keV band is 3.1 +- 0.4 x 10^-6
erg/cm2. The 1-sec peak photon flux measured from T+0.26 sec in the 15-150
keV band is 3.6 +- 0.4 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/1516528

(In memory of Scott Barthelmy, the BAT team dedicates the rest of our
circulars to Scott.)