{
  "bibcode": "2019GCN.24715....1F",
  "body": "D. Frederiks, S. Golenetskii, R.Aptekar, A. Kozlova,\nA.Lysenko,  D. Svinkin, A. Tsvetkova,  M. Ulanov, and T. Cline,\non behalf of the Konus-Wind team, report:\n\nThe extremely bright, long GRB 190530A\n(Fermi GBM detection: GCN 24676,24692; AGILE-MCAL detection: GCN 24679;\nFermi-LAT detection: GCN 24679; AGILE/GRID analysis: GCN 24683;\nAstroSat CZTI detection: GCN 24694) triggered Konus-Wind (KW)\nat T0=37146.000 s UT (10:19:06.000).\n\nThe light curve of the burst shows a bright, multi-peaked pulse\nwith a total duration of ~55s, followed by a weaker and softer\nemission tail visible until ~T0+150 s.\nThe emission in the bright phase of the burst is seen up to ~10 MeV.\nThe Konus-Wind light curve of this GRB is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB190530_T37146/\n\nAs observed by Konus-Wind, the burst had\na fluence of (5.57 �� 0.15)x10^-4 erg/cm2 and\na 64-ms peak energy flux, measured from T0+14.912,\nof (1.59 �� 0.10)x10^-4 erg/cm2 (both in the 20 keV - 10 MeV\nenergy range).\n\nThe time-integrated spectrum (measured from T0 to T0+44.228 s)\nis best fit in the 20 keV - 16 MeV range\nby the GRB (Band) function with the following model parameters:\nthe low-energy photon index alpha = -1.03 (-0.02,+0.02),\nthe high energy photon index beta = -3.03 (-0.36,+0.22),\nthe peak energy Ep = 848 (-33,+44) keV,\nchi2 = 140/96 dof.\n\nThe spectrum near the peak count rate (measured from T0+14.848 s\nto T0+15.104 s) is best fit in the 20 keV - 16 MeV range\nby a cutoff power-law (CPL) function with the following model\nparameters: the photon index alpha = -0.41(-0.07,+0.07),\nand the peak energy Ep = 1176(-46,+47) keV, chi2 = 55/60 dof.\nFitting this spectrum with the GRB (Band) function yields\nthe same alpha and Ep, and an upper limit on beta of -3.2.\n\nAssuming an upper limit on the burst redshift z<2.2 (Heintz et al.,\nGCN 24686) and a standard cosmology with H_0 = 70 km/s/Mpc,\nOmega_M = 0.30, and Omega_Lambda = 0.70, we estimate the following\nupper limits on the GRB rest-frame energetics: the isotropic energy\nrelease E_iso < 6.4x10^54 erg and the peak luminosity L_iso < 5.8x10^54\nerg/s (both in the bolometric 1-10000 keV range).\nLocation of GRB 190530A in rest-frame hardness-intensity planes,\nalong with 'Amati' and 'Yonetoku' relations for the KW sample of\nGRBs with known redshifts (Tsvetkova et al., ApJ 850 161, 2017), can be\nfound at http://www.ioffe.ru/LEA/GRBs/GRB190530_T37146/GRB190530A.pdf\n\nAll the quoted errors are estimated at the 90% confidence level.\nAll the presented results are preliminary.",
  "circularId": 24715,
  "createdOn": 1559488731000,
  "email": "fred@mail.ioffe.ru",
  "subject": "Konus-Wind observation of extremely bright GRB 190530A",
  "submitter": "Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>",
  "eventId": "GRB 190530A"
}