{
  "bibcode": "2019GCN.23633....1P",
  "body": "K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U.\nLeicester), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Melandri\n(INAF-OAB), D.N. Burrows (PSU), A. Tohuvavohu (PSU), S. J. LaPorte\n(PSU) and V. Yurkov report on behalf of the Swift-XRT team: report on\nbehalf of the Swift-XRT team:\n\nWe have analysed 5.7 ks of XRT data for GRB 190106A (Yurkov et al. GCN\nCirc. 23614), from 85 s to 44.7 ks after the  BAT trigger. The data\ncomprise 254 s in Windowed Timing (WT) mode with the remainder in\nPhoton Counting (PC) mode. The enhanced XRT position for this burst was\ngiven by Goad et al. (GCN Circ. 23619).\n\nThe late-time light curve (from T0+11.7 ks) can be modelled with a\npower-law decay with a decay index of alpha=1.02 (+/-0.11).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 2.06 (+0.06, -0.05). The\nbest-fitting absorption column is  1.9 (+/-1.1) x 10^21 cm^-2, at a\nredshift of 1.86, 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 1.95 (+0.09, -0.06) and a best-fitting absorption column consistent\nwith the Galactic value. The counts to observed (unabsorbed) 0.3-10 keV\nflux conversion factor deduced from this spectrum  is 3.5 x 10^-11 (4.4\nx 10^-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:    1.0 (+1.6, -0.0) x 10^21 cm^-2 at z=1.86\nPhoton index:\t     1.95 (+0.09, -0.06)\n\nIf the light curve continues to decay with a power-law decay index of\n1.02, the count rate at T+24 hours will be 0.096 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.4 x\n10^-12 (4.2 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/00882252.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 23633,
  "createdOn": 1546868703000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 190106A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 190106A"
}