{
  "circularId": 39152,
  "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 250201A (Fermi-GBM detection: Fermi GBM team, GCN 39112;\nBALROG localization: Preis & Greiner, GCN 39113;\nINTEGRAL SPI/ACS detection: Barria et al., GCN 39117;\nIPN triangulation: Kozyrev et al., GCN 39151)\ntriggered Konus-Wind (KW) at T0=35989.814 s UT (09:59:49.814).\n\nThe burst light curve shows a double-peaked emission pulse\nwith the total duration of ~21 s.\nThe emission is seen up to ~8 MeV.\n\nThe Konus-Wind light curve of this GRB is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB250201_T35989/\n\nAs observed by Konus-Wind, the burst had\na fluence of (1.21 ± 0.08)x10^-5 erg/cm^2 and\na 64-ms peak energy flux, measured from T0 + 12.160 s,\nof (2.97 ± 0.34)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+16.640 s)\nis best fit in the 20 keV - 15 MeV range\nby a GRB (Band) function with the following model parameters:\nthe low-energy photon index alpha = -0.72 (-0.12,+0.13),\nthe high energy photon index beta = -3.07 (-0.54,+0.27),\nthe peak energy Ep = 134 (-7,+8) keV,\nchi2 = 118/97 dof.\n\nThe spectrum near the peak count rate (measured from T0+8.448 s to T0+16.640 s)\nis best fit in the 20 keV - 15 MeV range\nby a GRB (Band) function with the following model parameters:\nthe low-energy photon index alpha = -0.76 (-0.11,+0.13),\nthe high energy photon index beta = -2.95 (-0.34,+0.23),\nthe peak energy Ep = 138 (-8,+8) keV,\nchi2 = 94/78 dof.\n\nAll the quoted errors are estimated at the 68% confidence level.\nAll the presented results are preliminary.\n",
  "bibcode": "2025GCN.39152....1F",
  "subject": "Konus-Wind detection of GRB 250201A",
  "submitter": "Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>",
  "submittedHow": "email",
  "eventId": "GRB 250201A",
  "createdOn": 1738772307952
}