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GCN Circular 36510

Subject
GRB 240516A: Swift-BAT refined analysis
Date
2024-05-17T21:45:50Z (2 months ago)
From
Amy <yarleen@gmail.com>
Via
email
S. Laha (GSFC/UMBC), S. D. Barthelmy (GSFC),
R. Gupta (GSFC), H. A. Krimm (NSF),
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-200 to T+200 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 240516A (trigger #1228797)
(Parsotan et al., GCN Circ. 36493).  The BAT ground-calculated position is
RA, Dec = 212.784, -63.495 deg which is
   RA(J2000)  =  14h 11m 08.3s
   Dec(J2000) = -63d 29' 41.7"
with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 45%.

The mask-weighted light curve shows a single-peaked, FRED-like structure
that starts at ~T-5 s, peaks at ~T-2 s, and ends at ~T+15 s. In addition,
there are some weak tail emissions that last till ~T+110 s.
T90 (15-350 keV) is 94.69 +- 34.00 sec (estimated error including
systematics).

The time-averaged spectrum from T-4.75 to T+112.50 sec is best fit by
a simple power-law model.  The power law index of the time-averaged
spectrum is 1.09 +- 0.19.  The fluence in the 15-150 keV band
is 2.0 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured
from T-2.20 sec in the 15-150 keV band is 1.1 +- 0.3 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/1228797

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