{
  "eventId": "GRB 260131A",
  "createdOn": 1769954786267,
  "body": "D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin,\nA. Tsvetkova,  M. Ulanov, and T. Cline,\non behalf of the Konus-Wind team, report:\n\nThe long GRB 260131A/B (Fermi-GBM detection:\nThe Fermi GBM team, GCN 43579, Roberts, GCN 43585;\nMAXI/GSC detection: Sugai et al., GCN 43580)\ntriggered Konus-Wind (KW) at T0=23972.646 s UT (06:39:32.646).\n\nThe burst consists of two separated emission pulses,\npeaked around ~T0 and to T0+215 s, respectively.\nThe total duration of the burst is ~250 s.\n\nThe Konus-Wind light curve of this GRB is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB260131_T23972/\n\nAs observed by Konus-Wind, the burst had\na fluence of (4.14 ± 0.91)x10^-5 erg/cm^2 and\na 64-ms peak energy flux, measured from T0 + 0.384 s,\nof (4.33 ± 0.52)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).\n\nThe time-integrated spectrum (measured from T0 to T0+238 s)\nis best fit in the 20 keV - 15 MeV range by a GRB (Band) function\nwith the following model parameters:\nthe low-energy photon index alpha = -0.15 (-0.70,+1.61),\nthe high energy photon index beta = -1.97 (-0.20,+0.14),\nthe peak energy Ep = 124 (-40,+56) keV,\nchi2 = 83/97 dof.\n\nThe spectrum near the peak count rate (measured from T0 to T0+8.448 s)\nis best fit in the 20 keV - 15 MeV range by a GRB (Band) function\nwith the following model parameters:\nthe low-energy photon index alpha = -1.17 (-0.15,+0.17),\nthe high energy photon index beta = -1.98 (-0.18,+0.10),\nthe peak energy Ep = 300 (-68,+131) keV,\nchi2 = 74/79 dof.\n\nAll the quoted errors are estimated at the 68% confidence level.\nAll the presented results are preliminary.",
  "submittedHow": "email",
  "subject": "Konus-Wind detection of GRB 260131A/B",
  "circularId": 43590,
  "submitter": "Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>",
  "bibcode": "2026GCN.43590....1F"
}