{
  "bibcode": "2021GCN.30157....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 210606B (GECAM detection: Cai et al., GCN 30138;\nBALROG localization: Kunzweiler et al., GCN Circ. 30139;\nAGILE detection: Ursi et al., GCN 30142;\nFermi GBM detection:  Malacaria & Meegan, GCN 30147;\nIPN localization: Hurley et al., GCN Circ. 30154;)\ntriggered Konus-Wind (KW) at T0=81665.249 s UT (22:41:05.249).\n\nThe burst light curve contains two major emission episodes:\na bright, multi-peaked emission complex in the interval from ~T0-2 s to ~T0+30 s;\nand the second, much weaker episode, which starts at ~T0+195 s, and has a duration of ~70 s.\nThe emission in the main episode is seen up to ~2 MeV.\n\nThe Konus-Wind light curve of this GRB is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB210606_T81665/\n\nAs observed by Konus-Wind, the burst had\na fluence of (8.1 �� 0.7)x10^-5 erg/cm^2 and\na 64-ms peak energy flux, measured from T0 + 4.224 s,\nof (1.7 �� 0.2)x10^-5 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).\n\nThe spectrum of the main episode (measured from T0 to T0+33.024 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 = -1.04 (-0.06,+0.07),\nthe high energy photon index beta = -2.61 (-0.54,+0.24),\nthe peak energy Ep = 309 (-27,+31) keV,\nchi2 = 80/97 dof.\n\nThe spectrum of the second episode (measured from T0+193.536 to T0+259.072 s)\nis best fit in the 20 keV - 20 MeV range\nby the a simple power law with the photon index of 2.1 (-0.14,+0.15), chi2 = 94/99 dof.\n\nThe spectrum near the peak count rate (measured from T0+0.256\nto T0+13.824 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 = -1.08 (-0.07,+0.08),\nthe high energy photon index beta = -2.67 (-1.76,+0.33),\nthe peak energy Ep = 345 (-42,+48) keV,\nchi2 = 84/97 dof.\n\nAll the quoted errors are estimated at the 90% confidence level.\nAll the presented results are preliminary.",
  "circularId": 30157,
  "createdOn": 1623233208000,
  "email": "fred@mail.ioffe.ru",
  "subject": "Konus-Wind detection of GRB 210606B",
  "submitter": "Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>",
  "eventId": "GRB 210606B"
}