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GCN Circular 16560

GRB 140709B: Swift-BAT refined analysis
2014-07-10T02:19:39Z (10 years ago)
Hans Krimm at NASA-GSFC <>
D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/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), C. A. Swenson (PSU), J. Tueller (GSFC),
T. N. Ukwatta (MSU) (i.e. the Swift-BAT team):

Using the data set from T-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 140709B (trigger #603866)
(Swenson, et al., GCN Circ. 16551).  The BAT ground-calculated position is
RA, Dec = 146.040, 63.536 deg which is
    RA(J2000)  =  09h 44m 09.5s
    Dec(J2000) = +63d 32' 10.0"
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 99%.

The mask-weighted light curve shows a complex structure.  The first peak has a
broad, symmetrical shape, starting at T-20 sec, peaking at T+25 sec and ending
at T+60 sec.  Then the second episode begins at T+80 sec, with multiple short
(~1-2 second) peaks extending to T+140 sec, before cutting off.  The highest of
these short peaks is at T+125 sec. T90 (15-350 keV) is 155.0 +- 22.3 sec
(estimated error including systematics).

The time-averaged spectrum from T-13.94 to T+197.51 sec is best fit by a power 
law with an exponential cutoff.  This fit gives a photon index 0.79 +- 0.30,
and Epeak of 152.6 +- 111.0 keV (chi squared 48.15 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 4.2 +- 0.2 x 10^-06 erg/cm2
and the 1-sec peak flux measured from T+123.63 sec in the 15-150 keV band is
0.9 +- 0.1 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.22 +- 0.07 (chi squared 54.91 for 57 d.o.f.).  All the quoted errors
are at the 90% confidence level.

The results of the batgrbproduct analysis are available at
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