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GCN Circular 14899

Subject
GRB 130615A: Swift-BAT refined analysis
Date
2013-06-15T15:56:13Z (12 years ago)
From
Scott Barthelmy at NASA/GSFC <scott@lheamail.gsfc.nasa.gov>
S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), E. Sonbas (NASA/GSFC/Adiyaman Univ.), M. Stamatikos (OSU),
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 recent telemetry downlinks,
we report further analysis of BAT GRB 130615A (trigger #558271)
(Sonbas, et al., GCN Circ. 14897Loading...
 
 ).  The BAT ground-calculated position is
RA, Dec = 274.963, -68.161 deg, which is 
   RA(J2000)  =  18h 19m 51.2s 
   Dec(J2000) = -68d 09' 39.7" 
with an uncertainty of 2.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 60%.
 
The mask-weighted light curve shows two peaks both of which are nearly smooth.
The first starts at ~T+10 sec and ends at ~T+150 se.  The second peak
goes from ~T+270 to T+450 sec.  T90 (15-350 keV) is 304 +- 30 sec
(estimated error including systematics).
 
The time-averaged spectrum from T+25.57 to T+386.86 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 0.87 +- 0.92, 
and Epeak of 33.2 +- 8.6 keV (chi squared 61.91 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 2.1 +- 0.3 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T+31.84 sec in the 15-150 keV band is
0.7 +- 0.2 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 2.18 +- 0.16 (chi squared 70.23 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/558271/BA/