{
  "bibcode": "2021GCN.30921....1R",
  "body": "A. Ridnaia, D. Frederiks, S. Golenetskii, A. Lysenko,\nD. Svinkin, A. Tsvetkova,  M. Ulanov, and T. Cline\non behalf of the Konus-Wind team, report:\n\nThe long-duration GRB 210928A\n(Fermi-LAT detection: Axelsson et al., GCN 30912;\nFermi-GBM observation: Fletcher & Meegan, GCN 30913)\ntriggered Konus-Wind at T0=7234.398 s UT (02:00:34.398).\n\nThe burst light curve shows a single multi-peaked pulse\nstarted at ~T0-4.3 s with a total duration of ~27.3 s.\nThe emission is seen up to ~6 MeV.\n\nThe Konus-Wind light curve of this GRB is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB210928_T07234/\n\nAs observed by Konus-Wind, the burst\nhad a fluence of 6.79(-0.66,+0.71)x10^-5 erg/cm2,\nand a 64-ms peak flux, measured from T0+14.416 s,\nof 6.45(-1.72,+1.77)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+24.320 s)\nis best fit in the 20 keV - 6 MeV range\nby the GRB (Band) model with the following parameters:\nthe low-energy photon index alpha = -0.34(-0.15,+0.16),\nthe high energy photon index beta = -2.55(-0.35,+0.21),\nthe peak energy Ep = 361(-33,+38) keV\n(chi2 = 61/78 dof).\n\nThe spectrum near the maximum count rate\n(measured from T0+8.448 to T0+16.128 s)\nis best fit in the 20 keV - 6 MeV range\nby the GRB (Band) model with the following parameters:\nthe low-energy photon index alpha = -0.07(-0.21,+0.23),\nthe high energy photon index beta = -2.73(-0.55,+0.28),\nthe peak energy Ep = 328(-30,+36) keV\n(chi2 = 75/78 dof).\n\nAll the quoted errors are at the 90% confidence level.\nAll the quoted values are preliminary.",
  "circularId": 30921,
  "createdOn": 1633351051000,
  "email": "ridnaia@mail.ioffe.ru",
  "subject": "Konus-Wind detection of GRB 210928A",
  "submitter": "Anna Ridnaia at Ioffe Institute  <ridnaia@mail.ioffe.ru>",
  "eventId": "GRB 210928A"
}