TITLE: GCN CIRCULAR NUMBER: 34846 SUBJECT: Konus-Wind detection of GRB 231018A DATE: 23/10/19 18:44:04 GMT FROM: Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru> D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin, Yu. Temiraev, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The long, bright GRB 231018A (Fermi GBM detection: Lesage et al., GCN 34831; IPN triangulation: Svinkin et al., GCN 34845) triggered Konus-Wind (KW) at T0=45043.083 s UT (12:30:43.083). The burst light curve shows a multi-peaked emission complex, which starts at ~T0-32 s, peaks at ~T0+28 s, and has a total duration of ~90 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/GRB231018_T45043/ As observed by Konus-Wind, the burst had a fluence of (1.17 ± 0.04)x10^-4 erg/cm^2 and a 64-ms peak energy flux, measured from T0 + 28.352 s, of (2.44 ± 0.10)x10^-5 erg/cm^2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum (measured from T0 to T0+38.912 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 = -1.34 (-0.05,+0.05), the high energy photon index beta = -2.92 (-0.17,+0.12), the peak energy Ep = 114 (-4,+4) keV, chi2 = 90/96 dof. The spectrum near the peak count rate (measured from T0+24.576 to T0+29.696 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 = -1.19 (-0.05,+0.06), the high energy photon index beta = -3.15 (-0.37,+0.24), the peak energy Ep = 146 (-7,+8) keV, chi2 = 67/73 dof. All the quoted errors are estimated at the 90% confidence level. All the presented results are preliminary. View this GCN Circular online at https://gcn.nasa.gov/circulars/34846. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...