GCN Circular 14702
Subject
GRB 130514A: Konus-Wind and Swift/BAT joint spectral analysis
Event
Date
2013-05-24T20:24:57Z (13 years ago)
From
Valentin Pal'shin at Ioffe Inst <val@mail.ioffe.ru>
V. Pal'shin, S. Golenetskii, R.Aptekar, E. Mazets, D. Frederiks, D.
Svinkin, M. Ulanov, and T. Cline on behalf of the Konus-Wind team,
T. Sakamoto (AGU), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC),
J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC),
H. Krimm (GSFC/USRA), C. Markwardt (GSFC), D. Palmer (LANL), M.
Stamatikos (OSU) and T. Ukwatta (GWU)
report:
We performed the Konus-Wind and the Swift/BAT joint spectral analysis of
GRB 130514A (Swift/BAT trigger #555821: Sonbas et al., GCN Circ. 14632,
Ukwatta et al. GCN Circ. 14636). Since the Konus-Wind observed this GRB
in the waiting mode, we only have 3 channel spectral data for the
Konus-Wind which cover the energy range from 20 keV to 1.2 MeV. The
joint spectral analysis of the Konus-Wind and the Swift/BAT data allows
us to derive the broad-band spectral parameters of this burst.
The time interval of the spectral data for each instrument is chosen
from T0(BAT)-5.1 to T0(BAT)+153.9 s where T0(BAT) is the trigger time of
BAT at 07:13:41 UTC. This interval comprises whole burst as observed by
Konus-Wind and contains 87% of the total fluence in the 15-150 keV as
observed by BAT (Ukwatta et al. GCN Circ. 14636).
The energy ranges which we used in the joint spectral analysis are
20-1200 keV and 14-150 keV for the Konus-Wind and the Swift/BAT
respectively. The spectral data of two instruments are fitted with the
spectral model multiplied by the constant factor to take into account
the systematic effective area uncertainties in the response matrices of
each instrument.
The spectrum is well fitted with a power-law with exponential cutoff
model: dN/dE ~ E^{alpha}*exp(-(2+alpha)*E/Epeak). No systematic residual
from the best fit model is seen in the spectral data of each instrument.
The BAT constant factor is 0.83(-0.08,+0.10) (the KW constant factor is
fixed to 1). The best fit spectral parameters are: alpha =
-1.44(-0.14,+0.17) and Epeak = 110(-21,+42) keV (chi2/dof = 41.9/57).
The best fit spectral parameters for the GRB (Band) model fixing beta =
-2.5 are: alpha = -1.44(-0.15,+0.17), and Epeak = 108(-21,+45) keV
(chi2/dof = 43.6/57). The energy fluence in the 15-1200 keV band
calculated by a power-law with exponential cutoff model for this 159 s
interval is 1.40(-0.16,+0.21)x10^-5 erg/cm2.
Assuming a photo-z of 3.6 (Schmidl, Kann, and Greiner GCN Circ. 14634)
and a standard cosmology model with H_0 = 71 km/s/Mpc, Omega_M = 0.27,
Omega_Lambda = 0.73, the isotropic energy release is E_iso =
4.95(-0.67,+0.85)x10^53 erg in 1 keV to 10 MeV at the GRB rest frame
extrapolating the best exponential cutoff function fit.
All the quoted errors are at the 90% confidence level.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB130514A/