{
  "format": "text/plain",
  "body": "A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin,\nA. Tsvetkova,  M. Ulanov, and T. Cline,\non behalf of the Konus-Wind team, report:\n\nThe long-duration GRB 251108C\n(AstroSat-CZTI detection: Salunke et al., GCN 42664;\nIPN triangulation: Kozyrev et al., GCN 42680)\ntriggered Konus-Wind at T0=83283.415 s UT (23:08:03.415).\n\nThe burst light curve shows a multipeaked structure\nwhich starts at ~T0-0.2 s and has a total duration of ~8.5 s.\nThe emission is seen up to ~6 MeV.\n\nThe Konus-Wind light curve of this GRB is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB251108_T83283/\n\nAs observed by Konus-Wind, the burst\nhad a fluence of 1.51(-0.19,+0.23)x10^-5 erg/cm2,\nand a 64-ms peak flux, measured from T0-0.172 s,\nof 1.23(-0.23,+0.26)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+8.448 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 = -1.05(-0.10,+0.11)\nand Ep = 1415(-316,+464) keV (chi2 = 55/69 dof).\nFitting by a GRB (Band) model yields the same alpha and Ep,\nand an upper limit on the high energy photon index: beta < -1.7\n(chi2 = 53/68 dof).\n\nThe spectrum near the maximum count rate\n(measured from T0 to T0+0.256 s)\nis best fit in the 20 keV - 10 MeV range\nby a power law with exponential cutoff model\nwith  alpha = -0.96(-0.17,+0.22)\nand Ep = 2202(-834,+1554) keV (chi2 = 26/30 dof).\nFitting by a GRB (Band) model yields the same alpha and Ep,\nand an upper limit on the high energy photon index: beta < -1.4\n(chi2 = 26/29 dof).\n\nAll the quoted errors are at the 68% confidence level.\nAll the quoted values are preliminary.\n",
  "submitter": "Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>",
  "bibcode": "2025GCN.42685....1R",
  "subject": "Konus-Wind detection of GRB 251108C",
  "createdOn": 1763150862174,
  "circularId": 42685,
  "eventId": "GRB 251108C",
  "submittedHow": "web"
}