{
  "bibcode": "2021GCN.29358....1S",
  "body": "D. Svinkin, S. Golenetskii, 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, bright GRB 210121A\n(Insight-HXMT/HE detection: Xue et al., GCN Circ. 29346\nGECAM detection: Peng et al., GCN Circ. 29347;\nIPN triangulation: Hurley et al., GCN Circ. 29348)\ntriggered Konus-Wind at T0=67306.174 s UT (18:41:46.174).\n\nThe burst light curve shows a multipeaked structure\nwhich starts at ~T0-0.1 s and has a total duration of ~64 s.\nThe emission is seen up to ~7 MeV.\n\nThe Konus-Wind light curve of this GRB is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB210121_T67306/\n\nAs observed by Konus-Wind, the burst\nhad a fluence of 1.18(-0.10,+0.10)x10^-4 erg/cm2,\nand a 64-ms peak flux, measured from T0+1.072 s,\nof 3.00(-0.43,+0.43)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+22.784 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 = -0.59(-0.05,+0.06),\nthe high energy photon index beta = -3.03(-1.42,+0.43),\nthe peak energy Ep = 875(-69,+70) keV\n(chi2 = 110/97 dof).\n\nThe spectrum near the maximum count rate\n(measured from T0+0.256 s to T0+1.792 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 = -0.32(-0.08,+0.09),\nthe high energy photon index beta = -3.60(3.60,+0.68),\nthe peak energy Ep = 981(-88,+94) keV\n(chi2 = 82/97 dof).\n\nAll the quoted errors are at the 90% confidence level.\nAll the quoted values are preliminary.",
  "circularId": 29358,
  "createdOn": 1611677919000,
  "email": "svinkin@mail.ioffe.ru",
  "subject": "Konus-Wind detection of GRB 210121A",
  "submitter": "Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>",
  "eventId": "GRB 210121A"
}