{
  "bibcode": "2020GCN.28301....1S",
  "body": "D. Svinkin, D. Frederiks, A. Ridnaia, and A. Tsvetkova,\non behalf of the Konus-Wind team, report:\n\nFollowing the X-ray afterglow detection (GCN 28300) and\nthe identification of possible optical transient (GCN 28295)\nspatially coincident with the X-ray source,\nwe present a further analysis of the KW detection of\nthe short-duration, soft-spectrum, bright GRB 200826A\n(GCNs 28284, 28287, 28288, 28289, 28294).\n\nAs observed by KW the burst duration is T50=0.286+/-0.029 s\n(T90 = 0.772+/-0.188 s). The position of the GRB 200826A in\nthe hardness-duration diagram (logT50-logHR32) of 1610 KW bright GRBs\n(Svinkin et al., JPhCS 1400, 2, 022010, 2019)\nsuggests that the burst comes from the long/soft GRB population.\nThe figure showing the hardness-duration diagram is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB200826_T16195/GRB200826A_HRT50.png\nThe contours denote the 1 and 3 sigma confidence regions for\ntwo-dimensional Gaussian distributions. The HR32 is the ratio of counts\nin the 200-760 keV and 50-200 keV bands accumulated during burst\nduration. The vertical dashed line at T50=0.7 s marks the boundary used\nby Svinkin et al. 2019 to distinguish between short and long KW GRBs.\n\nAssuming the redshift of an underlying galaxy z=0.714 (GCN 28295)\nand a standard cosmology model with H_0 = 67.3 km/s/Mpc,\nOmega_M = 0.315, and Omega_Lambda = 0.685 (Planck Collaboration, 2014),\nwe estimate the following rest-frame parameters:\nthe isotropic energy release E_iso is ~4.7x10^51 erg,\nthe peak luminosity L_iso is ~1.6x10^52 erg/s,\nand the rest-frame peak energy of the time-integrated spectrum,\nEp,i, is ~115 keV.\n\nWith these values, GRB 200826A is within the 1 sigma prediction band of\nboth 'Amati' and 'Yonetoku' relations built for 138 Type II (long/soft) \nGRBs with known z (Tsvetkova et al., ApJ 850 161, 2017).\nMeanwile, in both Eiso-Ep,z and Liso-Ep,z planes,\nthe GRB 200826A position is inconsistent with\nshort-hard (Type I) GRB population,\nsee http://www.ioffe.ru/LEA/GRBs/GRB200826_T16195/GRB200826A.pdf\n\nThus, from the analysis of the KW detection, we conclude, that,\nGRB 200826A may be classified as Type II (long/soft, core-collapse origin).",
  "circularId": 28301,
  "createdOn": 1598639351000,
  "email": "svinkin@mail.ioffe.ru",
  "subject": "GRB 200826A: further analysis of the Konus-Wind data and classification",
  "submitter": "Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>",
  "eventId": "GRB 200826A"
}