{
  "bibcode": "2007GCN..6459....1G",
  "body": "S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks,\nand T. Cline on behalf of the Konus-Wind team report:\n\nThe long GRB 070521 (Swift-BAT trigger #279935:\nGuidorzi et al., GCN 6431; Palmer et al., GCN 6440) triggered\nKonus-Wind at T0=24691.587 s UT (06:51:31.587).\n\nThe burst started at T-T0 ~-33 s and had a duration of ~55 s.\nAs observed by Konus-Wind the burst\nhad a fluence of 1.81(-0.31, +0.06)x10^-5 erg/cm2,\nand a 64-ms peak flux measured from T0+5.312 s\n4.12(-1.07, +0.78)x10^-6 erg/cm2/s\n(both in the 20 keV - 1 MeV energy range).\nThe burst shows strong spectral evolution.\n\nThe time-integrated spectrum of the burst\n(from T0 to T0+23.808 s: this interval comprises ~80%\nof the burst total counts) can be fitted\n(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 = 0.93 +/- 0.12\nand Ep = 222(-21, +27) keV (chi2 = 43/56 dof).\n\nAll the quoted errors are at the 90% confidence level.\n\nThe Konus-Wind light curve of this GRB is available\nat http://www.ioffe.rssi.ru/LEA/GRBs/GRB070521_T24691/",
  "circularId": 6459,
  "createdOn": 1179938759000,
  "email": "val@mail.ioffe.ru",
  "subject": "Konus-Wind observation of GRB 070521",
  "submitter": "Valentin Pal'shin at Ioffe Inst  <val@mail.ioffe.ru>",
  "eventId": "GRB 070521"
}