{
  "bibcode": "2021GCN.29642....1R",
  "body": "A. Ridnaia, S. Golenetskii, D. Frederiks, M. Ulanov,\nD. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline\non behalf of the Konus-Wind team, report:\n\nThe long-duration GRB 210306A\n(Swift-BAT detection: D'Elia et al., GCN 29597, Laha et al., GCN 29617;\nFermi-LAT detection: Ohno et al., GCN 29602;\nFermi-GBM observation: Veres, GCN 29605)\ntriggered Konus-Wind at T0=14040.731 s UT (03:54:00.731).\n\nThe burst light curve shows a multi-peaked emission complex,\nwhich starts at ~T0-0.2 s and has a total duration of ~11 s.\nThe emission is seen up to ~1 MeV.\n\nThe Konus-Wind light curve of this GRB is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB210306_T14040/\n\nAs observed by Konus-Wind, the burst\nhad a fluence of 7.01(-0.45,+0.48)x10^-6 erg/cm2,\nand a 64-ms peak flux, measured from T0+7.648 s,\nof 3.99(-0.60,+0.67)x10^-6 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+16.640 s)\nis best fit in the 20 keV - 1 MeV range\nby a power law with exponential cutoff model:\ndN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)\nwith  alpha = -1.21(-0.20,+0.22)\nand Ep = 77(-7,+7) keV (chi2 = 48/49 dof).\nFitting by a GRB (Band) model yields the same alpha and Ep,\nand an upper limit on the high energy photon index: beta < -2.6\n(chi2 = 46/48 dof).\n\nThe spectrum near the peak count rate\n(measured from T0+0.256 to T0+8.448 s)\nis best fit in the 20 keV - 1 MeV range\nby the GRB (Band) model with the following parameters:\nthe low-energy photon index alpha = -1.17(-0.23,+0.30),\nthe high energy photon index beta = -2.97(-1.31,+0.34),\nthe peak energy Ep = 70(-7,+7) keV\n(chi2 = 56/49 dof).\n\nAll the quoted errors are at the 90% confidence level.\nAll the quoted values are preliminary.",
  "circularId": 29642,
  "createdOn": 1615370725000,
  "email": "ridnaia@mail.ioffe.ru",
  "subject": "Konus-Wind detection of GRB 210306A",
  "submitter": "Anna Ridnaia at Ioffe Institute  <ridnaia@mail.ioffe.ru>",
  "eventId": "GRB 210306A"
}