{
  "format": "text/plain",
  "circularId": 45242,
  "eventId": "GRB 260727A",
  "bibcode": "2026GCN.45242....1S",
  "body": "D. Svinkin, D. Frederiks, A. Lysenko, V. Panteleeva,\nA. Ridnaia, A. Tsvetkova, M. Ulanov, and T. Cline\non behalf of the Konus-Wind team, report:\n\nThe long-duration GRB 260727A\n(SVOM-ECLAIRs detection: Li et al., GCN 45220;\nAstroSat-CZTI detection: Harsha et al., GCN 45225;\nGlowbug detection: Cheung et al., GCN 45233)\ntriggered Konus-Wind at T0=1327.631 s UT (00:22:07.631).\n\nThe burst light curve shows a multi-peaked structure\nwhich starts at ~T0-11 s and has a total duration of ~30 s (75-1200 keV).\nThe emission is seen up to ~300 keV.\n\nThe Konus-Wind light curve of this GRB is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB260727_T01327/\n\nAs observed by Konus-Wind, the burst\nhad the total fluence of 1.15(-0.03,+0.03)x10^-5 erg/cm2,\nand the 64-ms peak flux, measured from T0+1.072 s,\nof 1.61(-0.30,+0.30)x10^-6 erg/cm2/s\n(both in the 20 keV - 10 MeV energy range).\n\nThe time-averaged spectrum of the burst\n(measured from T0 to T0+16.640 s)\nis best fit in the 20 keV - 10 MeV range\nby a power law with exponential cutoff model:\ndN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)\nwith alpha = -0.20(-0.11,+0.11)\nand Ep = 85(-2,+2) keV (chi2 = 107/98 dof).\nFitting by a GRB (Band) model yields the same alpha and Ep,\nand an upper limit on the high energy photon index: beta < -4.2\n(chi2 = 107/97 dof).\n\nThe spectrum near the maximum count rate\n(measured from T0+0.256 to T0+8.448 s)\nis best fit in the 20 keV - 10 MeV range\nby a power law with exponential cutoff model:\nwith alpha = 0.02(-0.14,+0.14)\nand Ep = 93(-3,+3) keV (chi2 = 80/82 dof).\nFitting by a GRB (Band) model yields the same alpha and Ep,\nand an upper limit on the high energy photon index: beta < -3.8\n(chi2 = 80/81 dof).\n\nAll the quoted errors are at the 68% confidence level.\nAll the quoted values are preliminary.",
  "submitter": "Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>",
  "createdOn": 1785243408860,
  "subject": "Konus-Wind detection of GRB 260727A",
  "eventType": [
    "GRB",
    "Gamma-ray Transient"
  ],
  "submittedHow": "web"
}