{
  "bibcode": "2015GCN.18516....1G",
  "body": "S. Golenetskii, R. Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik,\nM. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, A. Kozlova,\nand T. Cline on behalf of the Konus-Wind team, report:\n\nThe long-duration GRB 151027A\n(Swift-BAT trigger #661775: Maselli et al., GCN Circ. 18478,\nPalmer et al., GCN Circ. 18496;\nFermi GBM detection: Toelge et al., GCN Circ. 18492)\ntriggered Konus-Wind at T0=14304.154 s UT (03:58:24.154).\n\nThe burst light curve consists of at least three pulses\nwith a total duration of ~120 s.\nThe emission is seen up to ~5 MeV.\n\nThe Konus-Wind light curve of this GRB is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB151027_T14304/\n\nAs observed by Konus-Wind, the burst\nhad a fluence of 1.42(-0.21,+0.37)x10^-5 erg/cm2,\nand a 64-ms peak flux, measured from T0+0.432 s,\nof 2.22(-0.61,+0.62)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 - 5 MeV range\nby a power law with exponential cutoff model:\ndN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)\nwith  alpha = -1.44(-0.21,+0.24)\nand Ep = 173(-46,+135) keV (chi2 = 78/77 dof).\nFitting by a GRB (Band) model yields the same alpha and Ep,\nand an upper limit on the high energy photon index: beta < -2.0\n(chi2 = 77/76 dof)\n\nThe spectrum near the maximum count rate\n(measured from T0 to T0+8.448 s)\nis best fit in the 20 keV - 2 MeV range\nby a power law with exponential cutoff model:\ndN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)\nwith  alpha = -0.96(-0.28,+0.32)\nand Ep = 91(-11,+14) keV (chi2 = 56/61 dof).\nFitting by a GRB (Band) model yields the same alpha and Ep,\nand an upper limit on the high energy photon index: beta < -2.7\n(chi2 = 56/60 dof)\n\nAssuming the redshift z=0.81 (Perley et al., GCN Circ. 18487)\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 ~2.4x10^52 erg,\nthe peak luminosity L_iso is ~7x10^51 erg/s,\nand the rest-frame peak energy of the time-integrated spectrum,\nEp,i, is ~310 keV.\n\nAll the quoted errors are at the 90% confidence level.\nAll the quoted values are preliminary.",
  "circularId": 18516,
  "createdOn": 1446043409000,
  "email": "svinkin@mail.ioffe.ru",
  "subject": "Konus-Wind observation of GRB 151027A",
  "submitter": "Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>",
  "eventId": "GRB 151027A"
}