{
  "bibcode": "2022GCN.31646....1T",
  "body": "A. Tsvetkova, D. Frederiks, A. Lysenko, A. Ridnaia, D. Svinkin,\nM. Ulanov, and T. Cline on behalf of the Konus-Wind team, report:\n\nThe long-duration GRB 220219B\n(IPN triangulation: Svinkin et al., GCN 31624),\nconsistent with the optical transient ZTF22aabjpxh/AT2022cva\nreported by ZTF (Ho et al., GCN 31619),\ntriggered Konus-Wind at T0=34045.350 s UT (09:27:25.350).\n\nThe burst light curve consists of two broad pulses:\nthe first one lasts from ~T0-34 s to ~T0+13 s peaking at ~T0,\nthe second pulse lasts from ~T0+18 s to ~T0+45 s peaking at ~T0+20 s,\nThe emission is seen up to ~1 MeV.\n\nAs observed by Konus-Wind, the burst had\na fluence of the first pulse 1.21(-0.15,+0.16)x10^-5 erg/cm^2,\na fluence of the whole burst 1.76(-0.14,+0.12)x10^-5 erg/cm^2,\nand a 64-ms peak energy flux, measured from T0-0.064 s,\nof 1.76(-0.27,+0.52)x10^-6 erg/cm^2/s\n(all in the 20 keV - 10 MeV energy range).\n\nSince the main fraction of the first pulse was detected\nbefore the trigger, its spectral analysis was performed using\nthe KW 3-channel light curve data.\n\nModelling its spectrum (measured from T0-33.723 s to T0+13.380 s)\nby the exponential cutoff model:\ndN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep),\nyields alpha = -1.86(-0.09,+4.36) and Ep = 39(-24,+27) keV.\n\nFitting the most intense part of the first pulse\n(measured from T0-1.340 s to T0+1.604 s)\nwith by the exponential cutoff model yields\nalpha = -1.75(-0.20,+4.25) and Ep = 61(-46,+24) keV.\n\nThe spectrum of the second emission pulse\n(from T0+16.640 s to T0+49.408 s)\nis well described by a simple power law (PL) with the photon PL index\nof 2.60(-0.10,+0.10) and chi2/dof = 69.5/61.\n\nAssuming the redshift z = 0.293 (Fremling et al., GCN 31629)\nand a standard cosmology with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315,\nand Omega_Lambda = 0.685 (Planck Collaboration, 2014),\nwe estimate the following burst rest-frame parameters:\nthe isotropic energy release in the first pulse is\nEiso = 2.75(-0.34,+0.36)x10^51 erg,\nthe isotropic peak luminosity is Liso = 5.17(-0.79,+1.53)x10^50 erg/s;\nthe rest-frame peak energy of the first pulse is Epiz = 50(-31,+35) keV;\nand the rest-frame peak energy of the 'peak' spectrum is\nEppz = 79(-59,+31) keV.\n\nWith these values, GRB 220219B is within 68% prediction bands for\nfor both 'Amati' and 'Yonetoku' relations for the sample of >300 long KW\nGRBs with known redshifts (Tsvetkova et al., 2021, ApJ, 908, 83),\nsee http://www.ioffe.ru/LEA/GRBs/GRB220219_T34045/GRB220219B_rest_frame.pdf\n\nThe Konus-Wind light curve of this GRB is available at\nhttp://www.ioffe.ru/LEA/GRBs/GRB220219_T34045/\n\nAll the quoted errors are at the 90% confidence level.\nAll the quoted values are preliminary.",
  "circularId": 31646,
  "createdOn": 1645768466000,
  "email": "tsvetkova@mail.ioffe.ru",
  "subject": "Konus-Wind observation of GRB 220219B",
  "submitter": "Anastasia Tsvetkova at Ioffe Institute  <tsvetkova@mail.ioffe.ru>",
  "eventId": "GRB 220219B"
}