{
  "bibcode": "2025GCN.40512....1F",
  "eventId": "GRB 250520A",
  "subject": "Konus-Wind detection of GRB 250520A (short/hard)",
  "submittedHow": "email",
  "createdOn": 1747838570420,
  "submitter": "Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>",
  "version": 2,
  "format": "text/plain",
  "body": "D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin,\nA. Tsvetkova,  M. Ulanov, and T. Cline,\non behalf of the Konus-Wind team, report:\n\nThe short GRB 250520A (Swift detection: Eyles-Ferris et al., GCN 40491;\nSVOM/GRM observation: Wang et al., GCN 40495; AstroSat CZTI detection:\nTembhurnikar et al., GCN 40497)\ntriggered Konus-Wind (KW) at T0=9741.866 s UT (02:42:21.866).\n\nThe burst light curve shows a single pulse,\nwhich starts at ~T0-0.07 s and has a duration of ~0.26 s.\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/GRB250520_T09741/\n\nAs observed by Konus-Wind, the burst had the total fluence\nof (3.38 ± 0.75)x10^-6 erg/cm^2 and a 16-ms peak energy flux,\nmeasured from T0-0.032, of (3.49 ± 0.81)x10^-5 erg/cm^2/s\n(both in the 20 keV - 10 MeV energy range).\n\nThe time-integrated spectrum of the burst (measured from T0 to T0+0.192 s)\nis best fit in the 20 keV - 15 MeV range by a GRB (Band) function\nwith the following model parameters:\nthe low-energy photon index alpha = -0.48 (-0.27,+0.41),\nthe high energy photon index beta = -2.51 (-1.99,+0.47),\nthe peak energy Ep = 671 (-211,+247) keV,\nchi2 = 37/27 dof.\n\nThe spectrum near the peak count rate (measured from T0 to T0+0.064 s)\nis best fit in the 20 keV - 15 MeV range by a GRB (Band) function\nwith the following model parameters:\nthe low-energy photon index alpha = -0.67 (-0.27,+0.46),\nthe high energy photon index beta = -2.39 (-7.61,+0.53),\nthe peak energy Ep = 1099 (-505,+876) keV,\nchi2 = 11/17 dof.\n\n\nAll the quoted errors are estimated at the 68% confidence level.\nAll the presented results are preliminary.\n",
  "editedBy": "Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Dmitry Frederiks at Ioffe Institute <ddfrederiks@gmail.com>",
  "circularId": 40512,
  "editedOn": 1747923009123
}