{
  "bibcode": "2022GCN.31511....1F",
  "body": "D. Frederiks, A.Lysenko, A. Ridnaya, D. Svinkin, A. Tsvetkova,  M. Ulanov,\non behalf of the Konus-Wind team;\nand A. Melandri (INAF-OAB), A.Y. Lien (U Tampa), D.M. Palmer (LANL), S.D. Barthelmy (GSFC),\non behalf of the Swift-BAT team, report:\n\nThe long GRB 220117A (Swift-BAT trigger #1093592, T0 = T0(BAT)= 16:18:51.546 UT:\nMelandri et al. GCN 31466; Palmer et al., GCN 31485;\nFermi GBM Sub-Threshold Detection: Veres, GCN 31487)\nwas detected by Konus-Wind (KW) in the waiting mode.\n\nA Bayesian block analysis of the KW waiting mode data in the 20-400 keV band\nreveals a >10 sigma count rate increase over background in the interval\nfrom ~T0+10 s to ~T0+50 s. No statistically significant\nemission has been detected above 400 keV throughout the burst.\nThe KW light curve of this burst is available\nat http://www.ioffe.ru/LEA/GRBs/GRB220117A/\n\nTo derive broad-band spectral parameters of this burst, we performed\na joint spectral analysis of the Swift/BAT data (15-150 keV) and\nthe KW 3-channel spectral data (20-1500 keV).\nA fit to the time-averaged spectrum, measured from  T0+10.557 s to T0+48.829 s,\nby a power law with an exponential cutoff (CPL) model gives a photon index\nalpha = -1.14 (-0.32,+0.37), and Ep = 71 (-11,+17) keV, chi^2 = 65.0/ 58 dof.\nThe Band GRB function fits this spectrum equally well, with alpha = -1.04 (-0.40,+0.58),\nEp = 65 (-14,+20) keV, and beta = -2.59 (-7.41, +0.43), chi^2 = 64.7/57 dof.\nA fit to a simple power law gives a photon index of 1.89 (-0.08, +0.09), chi^2 = 72.4/ 59 dof.\n\nIn the 15-1500 keV band, the total burst fluence, estimated from the Band model,\nis (2.8 �� 0.7)x10^-6 erg/cm^2, and the 2.944 s peak energy flux is (1.7 �� 0.4)x10^-7 erg/cm^2/s.\n\nAssuming the redshift z=4.961 (Palmero et al., GCN 31480)\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 isotropic energy release E_iso to (1.26 �� 0.31)x10^53 erg,\nwhich is consistent with that estimated from the GBM detection (GCN 31487),\nthe isotropic peak luminosity L_iso to (4.5 �� 1.2)x10^52 erg/s,\nand the rest-frame peak energy of the time-integrated spectrum Ep,z to 387(-84,+120) keV.\nWith the obtained estimates, GRB 220117A lies inside 68% prediction bands\nfor both 'Amati' and 'Yonetoku' relations for the sample of >300 long KW GRBs\nwith known redshifts (Tsvetkova et al., 2017; Tsvetkova et al., 2021),\nsee http://www.ioffe.ru/LEA/GRBs/GRB220117A/GRB220117A_rest_frame.pdf",
  "circularId": 31511,
  "createdOn": 1642780466000,
  "email": "fred@mail.ioffe.ru",
  "subject": "GRB 220117A: Konus-Wind detection and joint Konus-Wind + Swift-BAT spectral analysis",
  "submitter": "Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>",
  "eventId": "GRB 220117A"
}