TITLE:   GCN CIRCULAR
NUMBER:  43413
SUBJECT: Konus-Wind detection of GRB 260114A
DATE:    26/01/15 12:44:01 GMT
FROM:    Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>

A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin,
A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

The short-duration GRB 260114A
(Fermi-GBM detection: Fermi GBM Team, GCN 43395; 
Bissaldi, GCN 43400;
Swift-BAT detection: Eyles-Ferris et al., GCN 43396;
GECAM-B observation: Ren et al., GCN 43402;
SVOM/GRM observation: Wang et al., GCN 43404)
triggered Konus-Wind at T0=42030.729 s UT (11:40:30.729).

The burst light curve shows a single pulse
which starts at ~T0 s and has a total duration of ~0.3 s.
The emission is seen up to ~2 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB260114_T42030/

As observed by Konus-Wind, the burst
had a fluence of 5.12(-0.25,+0.25)x10^-6 erg/cm2,
and a 16-ms peak flux, measured from T0+0.024 s,
of 2.76(-0.33,+0.33)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+0.256 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = 0.56(-0.15,+0.16)
and Ep = 502(-25,+26) keV (chi2 = 36/34 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -3.4
(chi2 = 36/33 dof).

Assuming the redshift z=0.524 (Yang et al., GCN 43410)
and a standard cosmology model with H_0 = 67.3 km/s/Mpc,
Omega_M = 0.315, and Omega_Lambda = 0.685 (Planck Collaboration, 2014),
we estimate the following rest-frame parameters:
the isotropic energy release E_iso is 3.86(-0.19,+0.19)x10^51 erg,
the peak luminosity L_iso is 3.17(-0.38,+0.38)x10^52 erg/s,
and the rest-frame peak energy of the time-integrated spectrum,
Ep,i, is 765(-38,+40) keV.

With the obtained estimates, the position of GRB 260114A in both Eiso-Ep,z and Liso-Ep,z planes 
is consistent with short-hard (Type I) GRB population, 
see http://www.ioffe.ru/LEA/GRBs/GRB260114_T42030/GRB260114A_rest_frame.pdf

All the quoted errors are at the 68% confidence level.
All the quoted values are preliminary.