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GCN Circular 20189

Subject
GRB 161117B: Swift-BAT refined analysis
Date
2016-11-17T18:40:10Z (8 years ago)
From
Hans Krimm at NSF/NASA-GSFC <hkrimm@nsf.gov>
T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),  J. R. Cummings (GSFC/UMBC),
N. Gehrels (GSFC), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), E. Troja (NASA/GSFC/UMCP), 
(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 161117B (trigger #722642)
(Troja, et al., GCN Circ. 20182).  The BAT ground-calculated position is
RA, Dec = 298.830, -67.681 deg which is 
   RA(J2000)  =  19h 55m 19.1s 
   Dec(J2000) = -67d 40' 51.8" 
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 43%.

The mask-weighted light curve shows a complex structure.  The first set of peaks
begins around T-10 sec, peaks at T+2 and fades by T+10 sec.  The second set 
of peaks begins around T+92 sec, peaks at T+102 sec and fades nearly to 
background by T+115 sec.  This is when the third set of peaks begins to rise,
which peaks at T+T+135 sec and fades by T+160 sec.  All of these peak 
structures have multiple sub-peaks. T90 (15-350 keV) is 152.51 +- 3.37 sec 
(estimated error including systematics).

The time-averaged spectrum from T-8.32 to T+157.44 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 1.39 +- 0.28, 
and Epeak of 37.5 +- 5.5 keV (chi squared 39.62 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 6.0 +- 0.2 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T+133.80 sec in the 15-150 keV band is
6.0 +- 0.3 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 2.14 +- 0.06 (chi squared 64.42 for 57 d.o.f.).  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/722642/BA/
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