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GCN Circular 27443

Subject
GRB 200324A, Swift-BAT refined analysis
Date
2020-03-25T21:13:14Z (4 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), S. Dichiara (NASA/GSFC/UMCP),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU) (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 200324A (trigger #963260)
(Dichiara et al., GCN Circ. 27428).  The BAT ground-calculated position is
RA, Dec = 222.682, 35.931 deg which is
   RA(J2000)  =  14h 50m 43.7s
   Dec(J2000) = +35d 55' 51.0"
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.

The mask-weighted light curve shows a weak pulse that starts
at ~T-40 s, peaks at ~T0, and lasts until >~T+80 s. The burst was
temporarily out of the BAT FOV from T+100.39 s to T+119.39 s.
There might be additional burst emission during this period.
Due to this data gap, the standard data analysis pipeline
is unable to estimate an accurate T90.

The time-averaged spectrum from T-38.1 to T+100.4 sec (before
the burst went out of the BAT FOV) is best fit by a simple power-law model.

The power law index of the time-averaged spectrum is 1.72 +- 0.15.
The fluence in the 15-150 keV band is 2.3 +- 0.2 x 10^-6 erg/cm2. The 1-sec
peak photon flux measured from T+0.07 sec in the 15-150 keV band
is 0.7 +- 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/963260/BA/
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