{
  "bibcode": "2019GCN.23880....1K",
  "body": "A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks,\nM. Ulanov,  D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline\non behalf of the Konus-Wind team, report:\n\nThe extremely bright, short-duration, hard-spectrum\nGRB 190206A (IPN triangulation: Svinkin et al., GCN Circ. 23879)\ntriggered Konus-Wind at T0=13763.926 s UT (03:49:23.926).\n\nThe burst light curve shows a single smooth pulse\nwhich starts at ~T0 s and has a total duration of ~0.1 s.\nThere is no evidence of an extended emission following the burst.\nThe emission is seen up to ~10 MeV.\n\nAs observed by Konus-Wind, the burst\nhad a fluence of 1.64(-0.17,+0.17)x10^-5 erg/cm2,\nand a 16-ms peak flux, measured from T0+0.004 s,\nof 6.44(-0.75,+0.76)x10^-4 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+0.064 s)\nis best fit in the 20 keV - 10 MeV range\nby a power law with exponential cutoff model:\ndN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)\nwith  alpha = -0.58(-0.10,+0.12)\nand Ep = 1600(-223,+248) keV (chi2 = 31/30 dof).\nFitting by a GRB (Band) model yields the same alpha and Ep,\nand an upper limit on the high energy photon index: beta < -2.3\n(chi2 = 30/29 dof).\n\nThe Konus-Wind light curve of this GRB is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB190206_T13763/\n\nThe spectrum of the burst is typical of short-hard GRBs.\nAssuming the measured fluxes, GRB 190206A is the third-brightest\nshort GRB detected by KW since November, 1994 in terms of peak flux,\nand among the dozen brightest short GRBs, in terms of the fluence\n(Svinkin et al. 2016, ApJS 224 10).\n\nAlthough the redshift of GRB 190206A is not available (yet),\na comparison of the provisional track of the burst in the Ep,z-Eiso\nand Ep,z-Liso planes with the KW sample of GRBs with known redshifts\n(Tsvetkova et al., 2017, ApJ 850 161) suggests z < 0.5\n(see http://www.ioffe.ru/LEA/GRBs/GRB190206_T13763/GRB190206A_z.pdf).\n\nAll the quoted errors are at the 90% confidence level.\nAll the quoted values are preliminary.",
  "circularId": 23880,
  "createdOn": 1549478013000,
  "email": "ann_kozlova@mail.ioffe.ru",
  "subject": "Konus-Wind observation of GRB 190206A",
  "submitter": "Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>",
  "eventId": "GRB 190206A"
}