{
  "bibcode": "2019GCN.24823....1P",
  "body": "K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U.\nLeicester), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), A.\nTohuvavohu (PSU), S. J. LaPorte (PSU), J.A. Kennea (PSU) and A. D'Ai\nreport on behalf of the Swift-XRT team:\n\nWe have analysed 6.3 ks of XRT data for GRB 190613B (D'Ai et al. GCN\nCirc. 24807), from 103 s to 19.3 ks after the  BAT trigger. The data\ncomprise 352 s in Windowed Timing (WT) mode with the remainder in\nPhoton Counting (PC) mode. The enhanced XRT position for this burst was\ngiven by Beardmore et al. (GCN Circ. 24812).\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=0.52 (+/-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 1.93 (+/-0.05). The\nbest-fitting absorption column is  3.28 (+0.24, -0.23) x 10^21 cm^-2,\nin excess of the Galactic value of 6.0 x 10^20 cm^-2 (Willingale et al.\n2013). The PC mode spectrum has a photon index of 1.90 (+/-0.11) and a\nbest-fitting absorption column of 2.6 (+0.5, -0.4) x 10^21 cm^-2. The\ncounts to observed (unabsorbed) 0.3-10 keV flux conversion factor\ndeduced from this spectrum  is 3.8 x 10^-11 (5.2 x 10^-11) erg cm^-2\ncount^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     2.6 (+0.5, -0.4) x 10^21 cm^-2\nGalactic foreground: 6.0 x 10^20 cm^-2\nExcess significance: 7.6 sigma\nPhoton index:\t     1.90 (+/-0.11)\n\nIf the light curve continues to decay with a power-law decay index of\n0.52, the count rate at T+24 hours will be 0.091 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.5 x\n10^-12 (4.8 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/00908329.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 24823,
  "createdOn": 1560463293000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 190613B: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 190613B"
}