{
  "eventType": [
    "GRB",
    "Gamma-ray Transient"
  ],
  "eventId": "GRB 261029C",
  "submitter": "Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>",
  "createdOn": 1793971879458,
  "subject": "Konus-Wind detection of GRB 261029C (short / bright)",
  "format": "text/plain",
  "circularId": 46171,
  "submittedHow": "web",
  "body": "D. Svinkin, D. Frederiks, A. Lysenko, V. Panteleeva, A. Ridnaia,\nA. Tsvetkova, M. Ulanov, and T. Cline\non behalf of the Konus-Wind team, report:\n\nThe bright, short-duration GRB 261029C\n(AstroSat-CZTI detection: Harsha et al., GCN 46129;\nIPN triangulation: Svinkin et al., GCN 46159)\ntriggered Konus-Wind at T0=85117.559 s UT (23:38:37.559).\n\nThe burst light curve shows a single bright peak\nwhich starts at ~T0-10 ms and has a duration of ~30 ms,\nfollowed by a weaker emission seen up to ~T0+350 ms.\nThe emission is seen up to ~10 MeV.\n\nThe Konus-Wind light curve of this GRB is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB261029_T85117/\n\nAs observed by Konus-Wind, the burst\nhad the total fluence of 8.27(-0.76,+0.80)x10^-6 erg/cm2,\nand the 16-ms peak flux, measured from T0-0.006 s,\nof 6.57(-1.08,+1.65)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+0.192 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 = -0.72(-0.14,+0.16),\nthe high energy photon index beta = -2.20(-0.59,+0.27),\nthe peak energy Ep = 1432(-361,+482) keV\n(PG-stat = 87/78 dof).\n\nSince a significant fraction of the main peak of the burst light curve\nwas detected before the trigger, we performed spectral analysis\nof the burst peak using the KW 3-channel light curve data.\n\nModelling the KW 3-channel time-integrated spectrum\n(measured from T0-0.010 s to T0+0.018 s)\nby a power law with exponential cutoff (CPL) model:\ndN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep),\nyields alpha = -0.70(-0.24,+0.26) and Ep = 645(-140,+300) keV.\n\nAll the quoted errors are at the 68% confidence level.\nAll the quoted values are preliminary."
}