{
  "bibcode": "2015GCN.18433....1G",
  "body": "S. Golenetskii, R. Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik,\nM. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, A.Kozlova and T. Cline\non behalf of the Konus-Wind team, report:\n\nThe long-duration, intense GRB 151021A (Swift-BAT trigger #660671:\nMelandri et al., GCN 18425; Krimm et al., GCN 18429)\ntriggered Konus-Wind at T0=5336.535 s UT (01:28:56.535).\n\nThe burst light curve shows a multi-peaked structure\nstarted at ~T0-6.1 s with a total duration of ~100 s.\nThe emission is seen up to ~10 MeV.\n\nThe Konus-Wind light curve of this GRB is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB151021_T05336/\n\nAs observed by Konus-Wind, the burst\nhad a fluence of 7.66(-0.87,+0.97)x10^-5 erg/cm2,\nand a 64-ms peak flux, measured from T0+22.256 s,\nof 4.92(-1.44,+1.41)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+131.328 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 = -1.14 (-0.14,+0.15),\nthe high energy photon index beta = -2.46 (-0.32,+0.18),\nthe peak energy 170 (-18,+23) keV\n(chi2 = 94/96 dof)\n\nThe spectrum near the maximum count rate\n(measured from T0+16.640 to T0+33.024 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 = -0.89 (-0.19,+0.19),\nthe high energy photon index beta = -2.29 (-0.32,+0.14),\nthe peak energy 200 (-27,+46) keV\n(chi2 = 73/96 dof)\n\nAssuming the redshift z=2.330 (de Ugarte Postigo et al., GCN 18426)\nand a standard cosmology model with H_0 = 70 km/s/Mpc,\nOmega_M = 0.27, and Omega_Lambda = 0.73,\nwe estimate the following rest-frame parameters:\nthe isotropic energy release E_iso is ~1.0x10^54 erg,\nthe peak luminosity L_iso is ~2.2x10^53 erg/s,\nand the rest-frame peak energy of the time-integrated spectrum,\nEp,i, is ~666 keV.\n\nAll the quoted errors are at the 90% confidence level.\nAll the quoted values are preliminary.",
  "circularId": 18433,
  "createdOn": 1445449263000,
  "email": "ann_kozlova@mail.ioffe.ru",
  "subject": "Konus-Wind observation of GRB 151021A",
  "submitter": "Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>",
  "eventId": "GRB 151021A"
}