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GCN Circular 17823

Subject
Konus-Wind observation of GRB 150514A
Date
2015-05-18T15:01:37Z (9 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik,
M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration GRB 150514A
(Fermi-LAT detection:  Kocevski & Arimoto , GCN 17816;
Fermi-GBM detection:  Roberts, Zhang & Meegan GCN 17819)
triggered Konus-Wind at 66905.130 s UT (18:35:05.130).

The KW light curve shows a single pulse with a duration of ~10 s.
The emission is visible up to ~5 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB150514_T66905/

As observed by Konus-Wind, the burst had a fluence
of 3.7(-0.7,+0.7)x10^-6 erg/cm2, and a 64-ms peak flux,
measured from T0+0.448 s, of 3.4(-0.6,+0.6)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum (measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 15 MeV range
by the cutoff power law with the following model parameters:
the photon index alpha = -1.44(-0.29,+0.33),
and the peak energy Ep = 60(-14,+10) keV,
chi2 = 87/89 dof.
Fitting this spectrum with the GRB (Band) function yields
the following model parameters:
the low-energy photon index alpha = -1.25 (-0.23,+0.26),
the high energy photon index beta < -2.52 (upper limit),
the peak energy Ep = 58 (-9, +9) keV,
chi2 = 85/88 dof.

Assuming the redshift z=0.807 (de Ugarte Postigo et al., GCN 17822)
and a standard cosmology model with H_0 = 70 km/s/Mpc,
Omega_M = 0.27, and Omega_Lambda = 0.73,
we estimate the following rest-frame parameters:
the isotropic energy release E_iso is ~6.3x10^51 erg,
the peak luminosity L_iso is ~1.0x10^52 erg/s,
and the rest-frame peak energy of the time-integrated spectrum,
Ep,i, is ~108 keV.

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
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