{
  "id": "1908.02892",
  "version": "v1",
  "published": "2019-08-08T00:56:02.000Z",
  "updated": "2019-08-08T00:56:02.000Z",
  "title": "Measuring the distances to quasars at high redshifts with strong lensing",
  "authors": [
    "Kai Liao"
  ],
  "comment": "7 pages, 5 figures, to appear in ApJ",
  "categories": [
    "astro-ph.CO"
  ],
  "abstract": "Strongly lensed quasars with time-delay measurements are well known to provide the \"time-delay distances\" $D_{\\Delta t}=(1+z_L)D_LD_S/D_{LS}$ and the angular diameter distances to lens galaxies $D_L$. These two kinds of distances give stringent constraints on cosmological parameters. In this work, we explore a different use of time-delay observables: Under the assumption of a flat Universe, strong lensing observations can accurately measure the angular diameter distances to sources $D_S$. The corresponding redshifts of quasars may be up to $z_S\\sim4$ according to the forecast. The high-redshift distances would sample the Hubble diagram between SNe Ia and CMB, cosmological-model-independently providing direct information on the evolution of the nature of our Universe, for example, the dark energy Equation-of-State parameter $w(z)$. We apply our method to the existing lensing system SDSS 1206+4332 and get $D_S=2388_{-978}^{+2632}Mpc$ at $z_S=1.789$. We also make a forecast for the era of LSST. The uncertainty of $D_S$ depends on the redshifts of lens and source, the uncertainties of $D_{\\Delta t}$ and $D_L$, and the correlation between $D_{\\Delta t}$ and $D_L$ as well. Larger correlation would result in tighter $D_S$ determination.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2019-08-08T00:56:02.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "high redshifts",
      "strong lensing",
      "angular diameter distances",
      "dark energy equation-of-state parameter",
      "high-redshift distances"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 7,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}