{
  "subject": "Konus-Wind detection of GRB 210406A",
  "eventId": "GRB 210406A",
  "bibcode": "2021GCN.29772....1R",
  "createdOn": 1617818319000,
  "circularId": 29772,
  "submitter": "Anna Ridnaia at Ioffe Institute  <ridnaia@mail.ioffe.ru>",
  "email": "ridnaia@mail.ioffe.ru",
  "body": "A. Ridnaia, D. Frederiks, S. Golenetskii, A. Lysenko, D. Svinkin,\nA. Tsvetkova,  M. Ulanov, and T. Cline, report:\n\nThe long GRB 210406A (INTEGRAL detection,\nT0 = T0(IBIS/ISGRI)= 17:11:28 UT: Mereghetti, et al., GCN 29767;\nFermi/GBM detection: Malacaria & Meegan, GCN 29771)\nwas detected by Konus-Wind (KW) in the waiting mode.\n\nA Bayesian block analysis of the KW waiting mode data in the 20-400 keV band\nreveals a >10 sigma count rate increase over background in the interval\nfrom ~T0-0.470 s to ~T0+73.130 s.\n\nAs observed by Konus-Wind, the burst had a fluence of\n9.13(-1.16,+1.40)x10^-6 erg/cm2 and a 2.944-s peak flux,\nmeasured in the interval starting from ~T0+5.418 s,\nof 5.74(-0.84,+0.97)x10^-7 erg/cm2/s\n(both in the 10 keV - 10 MeV energy range).\n\nModeling the K-W 3-channel time-integrated spectrum\n(from ~T0-0.470 s to ~T0+73.130 s)\nby a power law with exponential cutoff (CPL) model\ndN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)\nyields alpha = -1.04(-0.20,+0.35) and Ep = 176(-36,+54) keV.\n\nThe KW light curve of this burst is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB210406A/\n\nAll the quoted errors are estimated at the 1 sigma confidence level.\nAll the presented results are preliminary."
}