TITLE:   GCN CIRCULAR
NUMBER:  45191
SUBJECT: Konus-Wind detection of GRB 260714B
DATE:    26/07/21 15:33:10 GMT
FROM:    Valentina Panteleeva at Ioffe Institute <panteleevav228@gmail.com>

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

The long-duration GRB 260714B
(Fermi-GBM detection: The Fermi GBM team, GCN 45161;
Fermi-LAT detection: Gupta and  Lalla, GCN 45162;
AstroSat-CZTI detection: Pathak et al., GCN 45163;
GECAM-B detection: Ren et al., GCN 45174;
SVOM-GRM detection: Ren et al., GCN 45176;
Insight-HXMT-HE detection: Luo et al., GCN 45188) 
triggered Konus-Wind at T0=66206.858 s UT (18:23:26.858).

The burst light curve shows a multipeaked structure
which starts at ~T0-0.4 s and has a total duration of ~15.5 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/GRB260714_T66206/

As observed by Konus-Wind, the burst
had the total fluence of 3.09(-0.20,+0.23)x10^-5 erg/cm2,
and the 64-ms peak flux, measured from T0+2.640 s,
of 1.39(-0.15,+0.16)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+15.360 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -1.07(-0.04,+0.04),
the high energy photon index beta = -3.61(-6.39,+0.71),
the peak energy Ep = 595(-44,+55) keV
(chi2 = 122/94 dof).

The spectrum near the maximum count rate
(measured from T0+0.256 to T0+7.168 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.94(-0.05,+0.05),
the high energy photon index beta = -2.97(-1.36,+0.38),
the peak energy Ep = 605(-51,+56) keV
(chi2 = 66/79 dof).

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