{
  "bibcode": "2016GCN.19348....1M",
  "body": "A. Melandri (INAF-OAB), D.N. Burrows (PSU), T.G.R. Roegiers (PSU), L.M.\nMcCauley (PSU), K.L. Page (U. Leicester), C. Pagani (U. Leicester),\nA.P. Beardmore (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC)\nand H.A. Krimm report on behalf of the Swift-XRT team:\n\nWe have analysed 7.0 ks of XRT data for GRB 160425A (Krimm et al. GCN\nCirc. 19343), from 207 s to 18.4 ks after the  BAT trigger. The data\ncomprise 439 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. 19347).\n\nThe late-time light curve (from T0+6.1 ks) can be modelled with a\npower-law decay with a decay index of alpha=0.78 (+/-0.23).\n\nA spectrum formed from the WT mode data can be fitted with an absorbed\npower-law with a photon spectral index\tof 2.18 (+/-0.04). The\nbest-fitting absorption column is  5.26 (+0.23, -0.22) x 10^21 cm^-2,\nin excess of the Galactic value of 7.7 x 10^20 cm^-2 (Willingale et al.\n2013). The PC mode spectrum has a photon index of 2.76 (+0.19, -0.18)\nand a best-fitting absorption column of 5.7 (+/-0.8) x 10^21 cm^-2. The\ncounts to observed (unabsorbed) 0.3-10 keV flux conversion factor\ndeduced from this spectrum  is 2.9 x 10^-11 (9.0 x 10^-11) erg cm^-2\ncount^-1. \n\nA summary of the PC-mode spectrum is thus:\nTotal column:\t     5.7 (+/-0.8) x 10^21 cm^-2\nGalactic foreground: 7.7 x 10^20 cm^-2\nExcess significance: 10.6 sigma\nPhoton index:\t     2.76 (+0.19, -0.18)\n\nIf the light curve continues to decay with a power-law decay index of\n0.78, the count rate at T+24 hours will be 0.019 count s^-1,\ncorresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.5 x\n10^-13 (1.7 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/00684098.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 19348,
  "createdOn": 1461655387000,
  "email": "pae9@leicester.ac.uk",
  "subject": "GRB 160425A: Swift-XRT refined Analysis",
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "eventId": "GRB 160425A"
}