{
  "bibcode": "2021GCN.29426....1F",
  "body": "D. Frederiks, S. Golenetskii, A.Lysenko, A. Ridnaia,\nD. Svinkin, A. Tsvetkova,  M. Ulanov, and T. Cline,\non behalf of the Konus-Wind team, report:\n\nThe long GRB 210207B (Swift detection:  Lien et al., GCN 29420)\ntriggered Konus-Wind (KW) at T0=78768.813 s UT (21:52:48.813).\n\nThe burst light shows a multi-peaked emission complex,\nwhich starts at ~T0-50 s, peaks at ~T0, and has the total duration of ~110 s.\nThe emission in is seen up to ~2.5 MeV.\n\nThe Konus-Wind light curve of this GRB is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB210207_T78768/\n\nAs observed by Konus-Wind, the burst had\na fluence of (2.4 �� 0.8)x10^-5 erg/cm^2 and\na 64-ms peak energy flux, measured from T0+1.472,\nof (4.5 �� 0.8)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).\n\nThe time-averaged spectrum (measured from T0 to T0+65.792 s)\nis best fit in the 20 keV - 15 MeV range\nby a power law with exponential cutoff (CPL) model:\ndN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)\nwith  alpha = -0.85(-0.34,+0.44) and Ep = 334(-97,+237) keV (chi2 = 91/97 dof).\nFitting this spectrum by a Band function yields the same alpha and Ep,\nand an upper limit on the high energy photon index: beta < -2.15\n(chi2 =67/97 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 the CPL model\nwith  alpha = -0.46(-0.22,+0.25) and Ep = 497(-84,+120) keV (chi2 = 76/97 dof).\nFitting this spectrum by a Band function yields the same alpha and Ep,\nand an upper limit on the high energy photon index: beta < -2.33\n(chi2 =76/96 dof).\n\n\nAll the quoted errors are estimated at the 90% confidence level.\nAll the presented results are preliminary.",
  "circularId": 29426,
  "createdOn": 1612791392000,
  "email": "fred@mail.ioffe.ru",
  "subject": "Konus-Wind detection of GRB 210207B",
  "submitter": "Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>",
  "eventId": "GRB 210207B"
}