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GCN Circular 16020

Subject
GRB 140320A: Swift-BAT refined analysis
Date
2014-03-21T13:04:45Z (10 years ago)
From
Amy Lien at GSFC <amy.y.lien@nasa.gov>
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),
J. K. Cannizzo (NASA/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC),
H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/UMBC), C. B. Markwardt (GSFC),
T. Sakamoto (AGU), M. Stamatikos (OSU), J. Tueller (GSFC),
T. N. Ukwatta (MSU) (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 140320A (trigger #592544)
(Cannizzo, et al., GCN Circ. 16000Not found
 
 
).  The BAT ground-calculated position is
RA, Dec = 281.843, -11.188 deg which is
   RA(J2000)  =  18h 47m 22.4s
   Dec(J2000) = -11d 11' 18.5"
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 88%.

The mask-weighted light curve shows a double short-peaked structure starts
at ~T-0.1 s. The second peak starts immediately at the end of the first peak
at ~T+0.3 s, and ends at ~T+0.4 s. T90 (15-350 keV) is 0.45 +- 0.07 sec
(estimated error including systematics).

The time-averaged spectrum from T-0.08 to T+0.44 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.24 +- 0.36.  The fluence in the 15-150 keV band is 4.9 +- 1.0 x 10^-8 erg/cm2.
The 1-sec peak photon flux measured from T-0.32 sec in the 15-150 keV band
is 0.6 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

As noted in the Fermi/GBM circular (Younes et al.; GCN Circ. 16001Not found
 
 
), the pulse
at ~T+140 s initially reported in Cannizzo, et al. (GCN Circ. 16000Not found
 
 
) is
originated from a different source, the bursting pulsar GROJ1744-28.
Therefore, GRB 140320A is a short burst.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/592544/BA/