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GCN Circular 36769

Subject
GRB 240624A: Swift-BAT refined analysis
Date
2024-06-26T22:29:41Z (17 days ago)
From
Amy <yarleen@gmail.com>
Via
email
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),
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-240 to T+962 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 240624A (trigger #1238732)
(Klingler et al., GCN Circ. 36743).
The BAT ground-calculated position is
RA, Dec = 102.473, -6.534 deg which is
   RA(J2000)  =  06h 49m 53.6s
   Dec(J2000) = -06d 32' 02.8"
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 49%.

The mask-weighted light curve shows a main structure with some overlapping
pulses that starts at ~T-2 s and ends at ~T+6 s. The main peak occurs at
~T+1.5 s. T90 (15-350 keV) is 5.89 +- 2.25 sec (estimated error including
systematics).

The time-averaged spectrum from T-0.06 to T+7.04 sec is best fit by a power
law with an exponential cutoff.  This fit gives a photon index 0.07 +-
0.94, and Epeak of 78.3 +- 36.0 keV (chi squared 45.64 for 56 d.o.f.).  For
this model the total fluence in the 15-150 keV band is 4.5 +- 0.6 x 10^-7
erg/cm2 and the 1-sec peak flux measured from T+0.88 sec in the 15-150 keV
band is 2.2 +- 0.3 ph/cm2/sec.  A fit to a simple power law gives a photon
index of 1.33 +- 0.18 (chi squared 52.69 for 57 d.o.f.).  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/1238732

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