{
  "submitter": "Phil Evans at U of Leicester <pae9@star.le.ac.uk>",
  "eventId": "GRB 231210B",
  "subject": "GRB 231210B: Swift-XRT refined Analysis",
  "bibcode": "2023GCN.35319....1O",
  "createdOn": 1702290238217,
  "submittedHow": "email",
  "circularId": 35319,
  "body": "J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), M. Capalbi\n(INAF-IASFPA), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR),\nJ.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), D.N. Burrows (PSU) and\nP.A. Evans report on behalf of the Swift-XRT team:\n\nWe have analysed 6.4 ks of XRT data for GRB 231210B, from 410 s to 35.6\nks after the  BAT trigger. The data comprise 40 s in Windowed Timing\n(WT) mode with the remainder in Photon Counting (PC) mode. \n\nThe light curve can be modelled with a power-law decay with a decay\nindex of alpha=1.32 (+0.05, -0.04).\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index of 1.65 (+0.11, -0.10). The\nbest-fitting absorption column is  5.3 (+7.7, -5.3) x 10^21 cm^-2, at a\nredshift of 3.13, in addition to the Galactic value of 4.1 x 10^20\ncm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed)\n0.3-10 keV flux conversion factor deduced from this spectrum  is 4.0 x\n10^-11 (4.3 x 10^-11) erg cm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nGalactic foreground: 4.1 x 10^20 cm^-2\nIntrinsic column:    5.3 (+7.7, -5.3) x 10^21 cm^-2 at z=3.13\nPhoton index:\t     1.65 (+0.11, -0.10)\n\nIf the light curve continues to decay with a power-law decay index of\n1.32, the count rate at T+24 hours will be 4.5 x 10^-3 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.8 x\n10^-13 (1.9 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/01201696.\n\nThis circular is an official product of the Swift-XRT team.\n"
}