{
  "bibcode": "2023GCN.34117....1K",
  "circularId": 34117,
  "createdOn": 1688020948083,
  "body": "J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), K.L. Page (U.\nLeicester), A.P. Beardmore (U. Leicester), M. Capalbi (INAF-IASFPA), M.\nPerri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), D.N. Burrows\n(PSU) and P.A. Evans report on behalf of the Swift-XRT team:\n\nWe have analysed 6.3 ks of XRT data for GRB 230628E, from 226 s to 22.6\nks after the  BAT trigger. The data are entirely in Photon Counting\n(PC) mode. \n\nThe light curve can be modelled with a power-law decay with a decay\nindex of alpha=0.85 (+/-0.05).\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index of 1.94 (+/-0.18). The\nbest-fitting absorption column is  9.5 (+4.9, -4.3) x 10^20 cm^-2, in\nexcess of the Galactic value of 4.3 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 3.4 x 10^-11 (4.1 x 10^-11) erg\ncm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     9.5 (+4.9, -4.3) x 10^20 cm^-2\nGalactic foreground: 4.3 x 10^20 cm^-2\nExcess significance: 2.0 sigma\nPhoton index:\t     1.94 (+/-0.18)\n\nIf the light curve continues to decay with a power-law decay index of\n0.85, the count rate at T+24 hours will be 8.1 x 10^-3 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.8 x\n10^-13 (3.3 x 10^-13) erg cm^-2 s^-1.\n\nThe results of the XRT-team automatic analysis are available at\nhttp://www.swift.ac.uk/xrt_products/01177054.\n\nThis circular is an official product of the Swift-XRT team.\n\n",
  "eventId": "GRB 230628E",
  "submitter": "Phil Evans at U of Leicester <pae9@star.le.ac.uk>",
  "subject": "GRB 230628E: Swift-XRT refined Analysis"
}