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GCN Circular 37083

Subject

GRB 240805A: Swift-BAT refined analysis

Date

2024-08-06T20:26:06Z (5 months ago)

From

Rahul Gupta at NASA GSFC <rahul.gupta@nasa.gov>

Via

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-240 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 240805A (trigger #1246907)
(Dichiara, et al., GCN Circ. 37032Loading...
 
 ).  The BAT ground-calculated position is
RA, Dec = 190.919, -53.603 deg which is
   RA(J2000)  =  12h 43m 40.6s
   Dec(J2000) = -53d 36' 10.3"
with an uncertainty of 0.79 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 31%.

The mask-weighted BAT light curve shows a complex structure. T90 (15-350 keV) is 37.34 +- 6.22 sec (estimated error including systematics).

The time-averaged spectrum from T-3.936 to T+258.128 sec is best fit by a simple
power-law model. The power law index of the time-averaged spectrum is
1.21 +- 0.06.  The fluence in the 15-150 keV band is 8.7 +- 0.3 x 10^-06 erg/cm2.
The 1-sec peak photon flux measured from T+3.28 sec in the 15-150 keV band
is 8.0 +- 0.5 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/1246907