{
  "bibcode": "2019GCN.24608....1D",
  "body": "A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB),\nD.N. Burrows (PSU), A. Tohuvavohu (PSU), S. J. LaPorte (PSU), P.A.\nEvans (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U.\nLeicester) and T.N. Ukwatta report on behalf of the Swift-XRT team:\n\nWe have analysed 7.0 ks of XRT data for GRB 190519A (Ukwatta et al. GCN\nCirc. 24595), from 91 s to 46.8 ks after the  BAT trigger. The data\ncomprise 100 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. 24597).\n\nThe late-time light curve (from T0+13.7 ks) can be modelled with a\npower-law decay with a decay index of alpha=1.33 (+/-0.28).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 2.34 (+0.20, -0.18). The\nbest-fitting absorption column is  6.5 (+1.2, -1.1) x 10^21 cm^-2, in\nexcess of the Galactic value of 4.3 x 10^21 cm^-2 (Willingale et al.\n2013). The PC mode spectrum has a photon index of 1.79 (+0.13, -0.12)\nand a best-fitting absorption column of 6.8 (+1.1, -1.0) x 10^21 cm^-2.\nThe counts to observed (unabsorbed) 0.3-10 keV flux conversion factor\ndeduced from this spectrum  is 4.9 x 10^-11 (7.5 x 10^-11) erg cm^-2\ncount^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     6.8 (+1.1, -1.0) x 10^21 cm^-2\nGalactic foreground: 4.3 x 10^21 cm^-2\nExcess significance: 4.3 sigma\nPhoton index:\t     1.79 (+0.13, -0.12)\n\nIf the light curve continues to decay with a power-law decay index of\n1.33, the count rate at T+24 hours will be 0.020 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.0 x\n10^-12 (1.5 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/00904394.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 24608,
  "createdOn": 1558318721000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 190519A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 190519A"
}