{
  "bibcode": "2020GCN.28147....1F",
  "body": "D. Frederiks, D. Svinkin, S. Golenetskii, R.Aptekar, A.Lysenko,\nA. Ridnaia, A. Tsvetkova,  M. Ulanov, and T. Cline,\non behalf of the Konus-Wind team, report:\n\nThe GRB 200716C (Swift-BAT detection: Ukwatta et al., GCN 28124;\nFermi-LAT detection: Ohno et al., GCN 28130;\nAGILE-MCAL detection: Ursi et al., GCN 28133;\nFermi-GBM detection: Veres & Meegan, GCN 28135;\nCALET-GBM detection: Torii et al., GCN 28139;\nInsight-HXMT/HE detection: Xue et al., GCN 28145)\ntriggered Konus-Wind (KW) at T0=82658.337 s UT (22:57:38.337).\n\nThe burst light curve shows two bright, short, hard-spectrum pulses\nin the interval from ~T0-0.5 s to ~T0+2.5 s.\nBoth pulses are ~0.5 s wide and they are peaked\nat ~T0-0.128 s and ~T0+2.096 s, respectively.\nA much weaker post-burst emission is visible\nin the KW 20-80 keV band up to ~T0+75 s.\nThe emission in the main pulses is seen up to ~7 MeV.\n\nThe Konus-Wind light curve of this GRB is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB200716_T82658/\n\nAs observed by Konus-Wind, the burst had\na fluence of (1.2 +/- 0.2)x10^-5 erg/cm^2 and\na 64-ms peak energy flux, measured from T0+0.128 s,\nof (3.7 +/- 0.6)x10^-5 erg/cm^2/s\n(both in the 20 keV - 10 MeV energy range).\n\nThe time-integrated spectrum (measured from T0 to T0+8.448 s)\nis best fit in the 20 keV - 15 MeV range\nby a power law with exponential cutoff (CPL) model:\ndN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)\nwith  alpha = -1.07(-0.12,+0.14)\nand Ep = 652(-154,+241) keV (chi2 = 91/97 dof).\nFitting by a GRB (Band) model yields similar alpha and Ep,\nand an upper limit on the high energy photon index: beta < -2.0\n(chi2 =91/96 dof).\n\nThe spectrum near the peak count rate (measured from T0\nto T0+0.256 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 = -0.51 (-0.19,+0.31),\nthe high energy photon index beta = -2.23 (-0.58,+0.29),\nthe peak energy Ep = 616 (-200,+226) keV,\n(chi2 = 48/42 dof).\n\nAssuming the photo z=0.348 of a possible host galaxy (D'Avanzo, GCN 28132)\nand a standard cosmology 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 ~ 3.9x10^51 erg,\nthe peak luminosity L_iso ~ 1.6x10^52 erg/s,\nand the rest-frame peak energy of the time-integrated (peak)\nspectrum Ep,z ~ 880 keV (~830 keV).\n\nWith these values, GRB 200716C is a clear outlier in the 'Amati' relation\nbuilt for 138 KW GRBs with known z (Tsvetkova et al., ApJ 850 161, 2017).\nMeanwile, in both Eiso-Ep,z and Liso-Ep,z planes, the GRB 200716C position\nis consistent with short-hard (Type I) GRB population,\nsee http://www.ioffe.ru/LEA/GRBs/GRB200716_T82658/GRB200716C.pdf\n\nAll the quoted errors are estimated at the 68% confidence level.\nAll the presented results are preliminary.\n\n[GCN OPS NOTE(20jul20):  Please see GCN Circ 24128 for a couple corrections.]",
  "circularId": 28147,
  "createdOn": 1595201553000,
  "email": "svinkin@mail.ioffe.ru",
  "subject": "Konus-Wind observation of GRB 200716C",
  "submitter": "Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>",
  "eventId": "GRB 200716C"
}