TITLE: GCN CIRCULAR NUMBER: 42487 SUBJECT: Konus-Wind detection of GRB 251022A DATE: 25/10/27 17:16:14 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 GRB 251022A (Fermi-GBM detection: The Fermi GBM team, GCN 42380; Mukherjee & Meegan, GCN 42410; Fermi-LAT detection: Di Lalla et al., GCN 42384; SVOM/GRM observation: Ren et al., GCN 42484) triggered Konus-Wind (KW) at T0=81287.312 s UT (22:34:47.312). The burst consists of multiple emission pulses in the interval from T0-35 s to T0+90; the total duration of the burst is ~125 s. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB251022_T81287/ As observed by Konus-Wind, the burst had a fluence of (4.14 ± 0.71)x10^-5 erg/cm^2 and a 64-ms peak energy flux, measured from T0 + 23.168 s, of (1.09 ± 0.36)x10^-5 erg/cm^2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum (measured from T0 to T0+90.368 s) is best fit in the 20 keV - 15 MeV range by a GRB (Band) function with the following model parameters: the low-energy photon index alpha = -1.37 (-0.08,+0.07), the high energy photon index beta = -2.06 (-0.22,+0.13), the peak energy Ep = 178 (-38,+80) keV, chi2 = 96/97 dof. The spectrum near the peak count rate (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 15 MeV range by a GRB (Band) function with the following model parameters: the low-energy photon index alpha = -0.71 (-0.42,+0.80), the high energy photon index beta = -2.13 (-0.84,+0.24), the peak energy Ep = 161 (-56,+84) keV, chi2 = 91/97 dof. All the quoted errors are estimated at the 68% confidence level. All the presented results are preliminary. View this GCN Circular online at https://gcn.nasa.gov/circulars/42487. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...