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GCN Circular 30513

GRB 210724A: Swift-BAT refined analysis
2021-07-25T19:43:26Z (3 years ago)
Amy Lien at GSFC <>
S. Laha (GSFC/UMBC), S. D. Barthelmy (GSFC),
P. D'Avanzo (INAF-OAB), H. A. Krimm (NSF),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):

Using the data set from T-240 to T+962 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 210724A (trigger #1061482)
(D'Avanzo et al., GCN Circ. 30497).  The BAT ground-calculated position is
RA, Dec = 227.425, -6.279 deg which is
   RA(J2000)  =  15h 09m 41.9s
   Dec(J2000) = -06d 16' 42.9"
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 34%.

The mask-weighted light curve shows a multi-peaked structure
that starts at ~T-40 s and ends at ~T+25 s. The main peak
occurs at ~T0. T90 (15-350 keV) is 50.57 +- 9.54 sec (estimated
error including systematics).

The time-averaged spectrum from T-38.55 to T+25.50 sec is best
fit by a simple power-law model.  The power law index of the
time-averaged  spectrum is 2.30 +- 0.28.  The fluence in the
15-150 keV band is 1.8 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak
photon flux measured from T-0.51 sec in the 15-150 keV band
is 2.5 +- 0.8 ph/cm2/sec.  All the quoted errors are at the
90% confidence level.

The results of the batgrbproduct analysis are available at
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