TITLE:   GCN CIRCULAR
NUMBER:  39016
SUBJECT: Konus-Wind detection of GRB 250119B
DATE:    25/01/23 15:22:17 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 long-duration GRB 250119B
(Fermi-GBM detection: Fermi GBM team, GCN 38979;
Preis et al., GCN 38980; Pathak et al., GCN 39003;
INTEGRAL/SPI-ACS detection: Barria et al., GCN 38997;
Swift-BAT/GUANO detection: Ronchini et al., 39007
IPN triangulation: Kozyrev et al., GCN 39015)
triggered Konus-Wind at T0=30434.631 s UT (08:27:14.631).

The burst light curve shows two separated multipeaked emission episodes.
The first episode starts at ~T0-18.6 s and has a total duration of ~162 s,
the second starts at ~T0+233 s and lasts up to ~T0+274 s.
The emission is seen up to ~3 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB250119_T30434/

As observed by Konus-Wind, the burst
had a fluence of 1.36(-0.16,+0.16)x10^-4 erg/cm2,
and a 64-ms peak flux, measured from T0+31.440 s,
of 9.43(-1.10,+1.11)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+273.664 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 = -1.02(-0.08,+0.09),
the high energy photon index beta = -2.37(-0.35,+0.19),
the peak energy Ep = 332(-36,+43) keV
(chi2 = 95/96 dof).

The spectrum near the maximum count rate
(measured from T0+29.184 to T0+36.096 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 = -0.64(-0.08,+0.09),
the high energy photon index beta = -2.43(-0.17,+0.12),
the peak energy Ep = 297(-20,+23) keV
(chi2 = 85/79 dof).

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