Konus-Wind detection of GRB 241030A

The long-duration GRB 241030A (Fermi-GBM detection: Fermi GBM Team, GCN 37955; Swift-BAT detection: Klingler et al., GCN 37956; SVOM/GRM observation: Wang et al., GCN 37972; Fermi-LAT detection: Pillera et al., GCN 37979) triggered Konus-Wind at T0=20996.591 s UT (05:49:56.591). The burst light curve shows a multipeaked structure which starts at ~T0-112.7 s and has a total duration of ~210.4 s. The emission is seen up to ~10 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB241030_T20996/ As observed by Konus-Wind, the burst had a fluence of 5.48(-1.28,+1.95)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+26.448 s, of 3.45(-0.82,+0.89)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+103.168 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 = -0.99(-0.19,+0.40), the high energy photon index beta = -2.26(-0.61,+0.30), the peak energy Ep = 140(-43,+35) keV (chi2 = 123/87 dof). The spectrum near the maximum count rate (measured from T0+22.016 to T0+28.160 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 = -0.91(-0.21,+0.23) and Ep = 196(-35,+55) keV (chi2 = 91/88 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.2 (chi2 = 91/87 dof). Assuming the redshift z=1.411 (Zheng et al., (GCN 37959)) and a standard cosmology 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 2.84(-0.68,+1.04)x10^53 erg, the peak luminosity L_iso is 4.47(-1.07,+1.15)x10^52 erg/s, the rest-frame peak energy of the time-averaged spectrum Ep,i,z is 339(-103,+84) keV and the spectrum near the maximum count rate Ep,p,z is 473(-84,+133) keV. With the obtained estimates, GRB 241030A is inside 68% prediction bands for both 'Amati' and 'Yonetoku' relations derived for the sample of >300 long KW GRBs with known redshifts (Tsvetkova et al., 2017; Tsvetkova et al., 2021), see http://www.ioffe.ru/LEA/GRBs/GRB241030_T20996/GRB241030A_rest_frame.pdf All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.