TITLE:   GCN CIRCULAR
NUMBER:  43772
SUBJECT: Konus-Wind detection of GRB 260212A
DATE:    26/02/17 14:55:21 GMT
FROM:    Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>

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 260212A (Fermi-GBM detection:
The Fermi GBM team, GCN 43716; Neights and Meegan GCN 43740;
Glowbug detection: Cheung et al., GCN 43719;
SVOM-GRM detection: Zhang et al., GCN 43727;
GECAM-B detection: Zhang et al., GCN 43736;
AstroSat-CZTI detection: Salunke et al., GCN 43741;
IPN triangulation: Kozyrev et al., GCN 43769)
triggered Konus-Wind (KW) at T0=64149.637 s UT (17:49:09.637).

The burst light curve shows multiple emission pulses
in the interval from ~T0-0.5 s to ~T0+11 s.
The emission is seen up to ~2 MeV.
We also note a much weaker emission bump around T0+25 s,
which is visible only below 80 keV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB260212_T64149/

As observed by Konus-Wind, the burst had
the fluence of (6.81 ± 0.55)x10^-6 erg/cm^2 and
the 64-ms peak energy flux, measured from T0 + 0.640 s,
of (4.98 ± 0.40)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum of the burst (measured from T0 to T0+16.640 s)
is best fitted in the 20 keV - 15 MeV range by a power law with exponential
cutoff (CPL) model dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -1.16 (-0.10, + 0.10) and Ep = 115(-7,+9) keV, chi^2 = 97/93 dof.
Fitting this spectrum by a Band GRB function yields the same values
of alpha and Ep, and only an upper limit on the high energy photon
index beta of -2.7

The spectrum near the peak count rate (measured from T0 to T0+8.448 s)
is best fitted in the 20 keV - 15 MeV range by a CPL model
with alpha = -0.86 (-0.11, + 0.12)and Ep = 108(-8,+10) keV, chi^2 = 94/78 dof.
Fitting this spectrum by a Band function yields the same values
of alpha and Ep, and only an upper limit on the high energy photon
index beta of -3.2

All the quoted errors are estimated at the 68% confidence level.
All the presented results are preliminary