{
  "bibcode": "2021GCN.30694....1F",
  "body": "D. Frederiks, S. Golenetskii, A.Lysenko, A. Ridnaia,\nD. Svinkin, A. Tsvetkova,  M. Ulanov, and T. Cline,\non behalf of the Konus-Wind team, report:\n\nThe long GRB 210822A (Swift detection: Page et al., GCN 30677;\nGECAM detection: Wang et al., GCN 30678;\nFermi-LAT detection: Ohno et al., GCN 30687;\nAstroSat CZTI detection: Ohno et al., GCN 30693)\ntriggered Konus-Wind (KW) at T0=33502.974 s UT (09:18:22.974).\n\nThe burst light curve shows a bright, multi-peaked pulse\nwhich starts at ~T0-1 s and has a total duration of ~12 s,\nfollowed by a weaker decaying emission visible up to ~T0+50 s.\nThe emission in the main pulse is seen up to ~15 MeV.\n\nThe Konus-Wind light curve of this GRB is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB210822_T33502/\n\nAs observed by Konus-Wind, the burst had\na fluence of (1.20 �� 0.11)x10^-4 erg/cm^2 and\na 64-ms peak energy flux, measured from T0 + 0.320 s,\nof (3.25 �� 0.28)x10^-5 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).\n\nThe time-integrated spectrum (measured from T0 to T0+18.176 s)\nis best fit in the 20 keV - 20 MeV range\nby the GRB (Band) function with the following model parameters:\nthe low-energy photon index alpha = -0.64 (-0.06,+0.07),\nthe high energy photon index beta = -2.39 (-0.15,+0.12),\nthe peak energy Ep = 398 (-29,+30) keV,\nchi2 = 124/96 dof.\n\nThe spectrum near the peak count rate (measured from T0+4.096\nto T0+7.936 s) is best fit in the 20 keV - 15 MeV range\nby the GRB (Band) function with the following model parameters:\nthe low-energy photon index alpha = -0.59 (-0.15,+0.18),\nthe high energy photon index beta = -2.08 (-0.18,+0.12),\nthe peak energy Ep = 429 (-83,+108) keV,\nchi2 = 75/63 dof.\n\nAssuming the redshift z=1.736 (Zhu et al., GCN 30692)\nand a standard cosmology with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315,\nand Omega_Lambda = 0.685 (Planck Collaboration, 2014),\nwe estimate the isotropic energy release E_iso to (9.5 �� 0.8)x10^53 erg,\nthe isotropic luminosity L_iso to (7.0 �� 0.6)x10^53 erg/s,\nthe rest-frame peak energy of the time-integrated spectrum Epi,z to (1090 �� 80) keV,\nand the rest-frame peak energy of the 'peak' spectrum Epp,z to (1175 �� 250) keV.\nWith these values, GRB 210822A lies within 68% prediction bands\nfor both 'Amati' and 'Yonetoku' relations for the sample of >300 long KW GRBs\nwith known redshifts (Tsvetkova et al., 2021, ApJ, 908, 83),\nsee http://www.ioffe.ru/LEA/GRBs/GRB210702_T68826/GRB210822A_rest_frame.pdf\n\nAll the quoted errors are estimated at the 90% confidence level.\nAll the presented results are preliminary.",
  "circularId": 30694,
  "createdOn": 1629722290000,
  "email": "fred@mail.ioffe.ru",
  "subject": "Konus-Wind detection of GRB 210822A",
  "submitter": "Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>",
  "eventId": "GRB 210822A"
}