{
  "eventId": "GRB 231020A",
  "submitter": "Y. Temiraev at Ioffe Institute <yuri.temiraev@mail.ioffe.ru>",
  "submittedHow": "web",
  "subject": "Konus-Wind detection of GRB 231020A",
  "circularId": 35140,
  "createdOn": 1700509389182,
  "bibcode": "2023GCN.35140....1T",
  "body": "Y. Temiraev, D. Svinkin, D. Frederiks, M. Ulanov,\nA. Tsvetkova, A. Lysenko, A. Ridnaia, and T. Cline\non behalf of the Konus-Wind team, report:\n\nThe long-duration GRB 231020A\n(Fermi-GBM detection: The Fermi GBM team, GCN Circ. 34856;\nBala et al., GCN Circ. 34869;\nBALROG localization: Preis et al., GCN Circ. 34861;\nAstroSat-CZTI detection: Navaneeth et al., GCN Circ. 34880;\nGRID detection: Wang and Yang, GCN Circ. 34903;\nIPN triangulation: Kozyrev et al., GCN Circ. 34917)\ntriggered Konus-Wind at T0=68224.628 s UT (18:57:04.628).\n\nThe burst light curve shows a single pulse\nwhich starts at ~T0-8.0 s and has a total duration of ~14.2 s.\nThe emission is seen up to ~10 MeV.\n\nThe Konus-Wind light curve of this GRB is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB231020_T68224/\nNote: 'dip' in the count rate is due\nto the GRB source occultation by the s/c structure.\n\nAs observed by Konus-Wind, the burst\nhad a fluence of 3.37(-0.15,+0.17)x10^-5 erg/cm2,\nand a 64-ms peak flux, measured from T0+0.992 s,\nof 1.09(-0.17,+0.17)x10^-5 erg/cm2/s\n(both in the 20 keV - 10 MeV energy range).\n\nThe time-averaged spectrum of the burst\n(measured from T0 to T0+10.240 s)\nis best fit in the 20 keV - 10 MeV range\nby the GRB (Band) model with the following parameters:\nthe low-energy photon index alpha = -1.00(-0.12,+0.13),\nthe high energy photon index beta = -3.11(-0.51,+0.26),\nthe peak energy Ep = 131(-7,+7) keV\n(chi2 = 105/97 dof).\n\nThe spectrum near the maximum count rate\n(measured from T0 to T0+2.048 s)\nis best fit in the 20 keV - 10 MeV range\nby a power law with exponential cutoff model:\ndN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)\nwith alpha = -0.85(-0.10,+0.11)\nand Ep = 185(-9,+10) keV (chi2 = 91/69 dof).\nFitting by a GRB (Band) model yields the same alpha and Ep,\nand an upper limit on the high energy photon index: beta < -3.3\n(chi2 = 91/68 dof).\n\nAll the quoted errors are at the 90% confidence level.\nAll the quoted values are preliminary."
}