{
  "submittedHow": "web",
  "bibcode": "2026GCN.44722....1S",
  "circularId": 44722,
  "subject": "Konus-Wind detection of GRB 260527A (short/hard) ~4 min before EP260527a",
  "eventId": "GRB 260527A",
  "format": "text/plain",
  "submitter": "Dmitry Svinkin at Ioffe Institute <dmitrysvinkin@gmail.com>",
  "createdOn": 1779970301748,
  "body": "D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia,\nA. Tsvetkova, M. Ulanov, and T. Cline\non behalf of the Konus-Wind team, report:\n\nThe short-duration GRB 260527A\ntriggered Konus-Wind at T0=22572.142 s UT (06:16:12.142).\n\nThe burst light curve shows a multi-peaked structure\nwhich starts at ~T0-0.1 s and has a total duration of ~0.2 s.\nThe emission is seen up to ~10 MeV.\n\nThe burst occurred ~4 min before the Einstein Probe detection of EP260527a (Yang et al., GCN 44718),\nand also the KW ecliptic latitude response is consistent with the EP260527a position.\nThis suggests a common origin of two events, which will be further investigated.\n\nThe Konus-Wind light curve of this GRB is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB260527_T22572/\n\nAs observed by Konus-Wind, the burst\nhad the total fluence of 1.99(-0.46,+0.57)x10^-6 erg/cm2,\nand the 16-ms peak flux, measured from T0-0.008 s,\nof 3.09(-1.06,+1.28)x10^-5 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+0.064 s)\nis best fit in the 20 keV - 10 MeV range\nby the GRB (Band) model with the following parameters:\nthe low-energy photon index alpha = -0.67(-0.36,+0.46),\nthe high energy photon index beta = -2.13(-0.85,+0.36),\nthe peak energy Ep = 541(-204,+367) keV\n(pgstat = 33/45 dof).\n\nA power law with exponential cutoff model:\ndN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)\nwith alpha = -0.79(-0.42,+0.49)\nand Ep = 670(-240,+1097) keV \nfits this spectrum equally well (pgstat = 35/46 dof).\n\nAll the quoted errors are at the 68% confidence level.\nAll the quoted values are preliminary."
}