{
  "bibcode": "2022GCN.32340....1K",
  "body": "J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), A.P. Beardmore (U.\nLeicester), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), T.\nSbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB), M.G. Bernardini\n(INAF-OAB), B. Sbarufatti (PSU) and A. D'Ai report on behalf of the\nSwift-XRT team:\n\nWe have analysed 6.6 ks of XRT data for GRB 220706A (D'Ai et al. GCN\nCirc. 32329), from 87 s to 67.9 ks after the  BAT trigger. The data\ncomprise 578 s in Windowed Timing (WT) mode (the first 8 s were taken\nwhile Swift was slewing) with the remainder in Photon Counting (PC)\nmode. The enhanced XRT position for this burst was given by Goad et al.\n(GCN Circ. 32330).\n\nThe late-time light curve (from T0+4.4 ks) can be modelled with a\npower-law decay with a decay index of alpha=1.3 (+/-0.4).\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index of 2.33 (+0.15, -0.14). The\nbest-fitting absorption column is  6.0 (+/-0.8) x 10^21 cm^-2, in\nexcess of the Galactic value of 2.4 x 10^20 cm^-2 (Willingale et al.\n2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion\nfactor deduced from this spectrum  is 3.5 x 10^-11 (7.6 x 10^-11) erg\ncm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     6.0 (+/-0.8) x 10^21 cm^-2\nGalactic foreground: 2.4 x 10^20 cm^-2\nExcess significance: 12.4 sigma\nPhoton index:\t     2.33 (+0.15, -0.14)\n\nIf the light curve continues to decay with a power-law decay index of\n1.3, the count rate at T+24 hours will be 0.016 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.6 x\n10^-13 (1.2 x 10^-12) erg cm^-2 s^-1.\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/01114937.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 32340,
  "createdOn": 1657200968000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 220706A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 220706A"
}