{
  "id": "2011.06002",
  "version": "v1",
  "published": "2020-11-11T19:00:03.000Z",
  "updated": "2020-11-11T19:00:03.000Z",
  "title": "TDCOSMO VI: Distance Measurements in Time-delay Cosmography under the Mass-sheet transformation",
  "authors": [
    "Geoff C. -F. Chen",
    "Christopher D. Fassnacht",
    "Sherry H. Suyu",
    "Akın Yıldırım",
    "Eiichiro Komatsu",
    "Jose Luis Bernal"
  ],
  "comment": "11 pages, 8 figures",
  "categories": [
    "astro-ph.CO",
    "astro-ph.GA"
  ],
  "abstract": "Time-delay cosmography with gravitationally lensed quasars plays an important role in anchoring the absolute distance scale and hence measuring the Hubble constant, $H_{0}$, independent of traditional distance ladder methodology. A current potential limitation of time delay distance measurements is the \"mass-sheet transformation\" (MST) which leaves the lensed imaging unchanged but changes the distance measurements and the derived value of $H_0$. In this work we show that the standard method of addressing the MST in time delay cosmography, through a combination of high-resolution imaging and the measurement of the stellar velocity dispersion of the lensing galaxy, depends on the assumption that the ratio, $D_{\\rm s}/D_{\\rm ds}$, of angular diameter distances to the background quasar and between the lensing galaxy and the quasar can be constrained. This is typically achieved through the assumption of a particular cosmological model. Previous work (TDCOSMO IV) addressed the mass-sheet degeneracy and derived $H_{0}$ under the assumption of $\\Lambda$CDM model. In this paper we show that the mass sheet degeneracy can be broken without relying on a specific cosmological model by combining lensing with relative distance indicators such as supernovae type Ia and baryon acoustic oscillations, which constrain the shape of the expansion history and hence $D_{\\rm s}/D_{\\rm ds}$. With this approach, we demonstrate that the mass-sheet degeneracy can be constrained in a cosmological-model-independent way, and hence model-independent distance measurements in time-delay cosmography under mass-sheet transformations can be obtained.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-11-11T19:00:03.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "time-delay cosmography",
      "mass-sheet transformation",
      "tdcosmo vi",
      "mass-sheet degeneracy",
      "traditional distance ladder methodology"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 11,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}