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GCN Circular 32496

Subject

GRB 220826A: Swift-BAT refined analysis

Date

2022-08-27T19:50:26Z (2 years ago)

From

Amy Lien at GSFC <amy.y.lien@nasa.gov>

T. Sakamoto (AGU), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC),
R. Caputo (GSFC), 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 220826A (trigger #1121751)
(Caputo et al., GCN Circ. 32484Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 206.421, -44.036 deg which is
   RA(J2000)  =  13h 45m 41.0s
   Dec(J2000) = -44d 02' 10.1"
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 92%.

The mask-weighted light curve shows a multi-peaked structure that
starts at ~T0 and ends at ~T+13 s. There are roughly three main
peaks at ~T+1 s, ~T+7 s, and ~T+11 s. respectively.
T90 (15-350 keV) is 11.14 +- 1.02 sec (estimated error including
systematics).

The time-averaged spectrum from T-0.20 to T+13.01 sec is best fit
by a simple power-law model.  The power law index of the time-averaged
spectrum is 1.44 +- 0.10.  The fluence in the 15-150 keV band
is 1.2 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured
from T+6.58 sec in the 15-150 keV band is 2.6 +- 0.2 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/1121751/BA/