Konus-Wind detection of GRB 210524A

The long-duration GRB 210524A (Fermi-GBM detection: The Fermi GBM team, GCN Circ. 30071; IPN triangulation: Hurley et al., GCN Circ. 30076) triggered Konus-Wind at T0=18010.925 s UT (05:00:10.925). The burst light curve shows a multi-peaked structure which starts at ~T0-3.5 s and has a total duration of ~11.5 s. The emission is seen up to ~1 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB210524_T18010/ As observed by Konus-Wind, the burst had a fluence of 8.64(-0.52,+0.56)x10^-6 erg/cm2, and a 64-ms peak flux, measured from T0+2.752 s, of 3.76(-1.00,+1.00)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+8.448 s) is best fit in the 20 keV - 2 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.33(-0.19,+0.20) and Ep = 99(-10,+11) keV (chi2 = 45/56 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.7 (chi2 = 45/55 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.