{
  "bibcode": "2020GCN.27001....1O",
  "body": "J.P. Osborne (U. Leicester), M. Capalbi (INAF-IASFPA), M. Perri (ASDC),\nV. D'Elia (ASDC), J. D. Gropp (PSU), J.A. Kennea (PSU), A. Tohuvavohu\n(U. Toronto), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester)\nand P.A. Evans report on behalf of the Swift-XRT team:\n\nWe have analysed 6.5 ks of XRT data for GRB 200205B (Evans et al. GCN\nCirc. 26993), from 332 s to 46.4 ks after the  BAT trigger. The data\ncomprise 360 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 Beardmore\net al. (GCN Circ. 26999).\n\nThe late-time light curve (from T0+5.3 ks) can be modelled with a\npower-law decay with a decay index of alpha=0.76 (+0.14, -0.13).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 1.129 (+0.027, -0.026). The\nbest-fitting absorption column is  4.9 (+1.2, -1.1) x 10^21 cm^-2, at a\nredshift of 1.465, in addition to the Galactic value of 1.0 x 10^21\ncm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index\nof 1.93 (+0.19, -0.13) and a best-fitting absorption column of 1 (+35,\n-1) x 10^20 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux\nconversion factor deduced from this spectrum  is 3.5 x 10^-11 (4.2 x\n10^-11) erg cm^-2 count^-1. \n\nA summary of the PC-mode spectrum is thus:\nGalactic foreground: 1.0 x 10^21 cm^-2\nIntrinsic column:    1 (+35, -1) x 10^20 cm^-2 at z=1.465\nPhoton index:\t     1.93 (+0.19, -0.13)\n\nIf the light curve continues to decay with a power-law decay index of\n0.76, the count rate at T+24 hours will be 0.018 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.1 x\n10^-13 (7.4 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/00954519.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 27001,
  "createdOn": 1581007166000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 200205B: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 200205B"
}