{
  "id": "1806.10138",
  "version": "v1",
  "published": "2018-06-26T18:00:00.000Z",
  "updated": "2018-06-26T18:00:00.000Z",
  "title": "Spectropolarimetry of High Redshift Obscured and Red Quasars",
  "authors": [
    "Rachael M. Alexandroff",
    "Nadia L. Zakamska",
    "Aaron J. Barth",
    "Fred Hamann",
    "Michael A. Strauss",
    "Julian Krolik",
    "Jenny E. Greene",
    "Isabelle Paris",
    "Nicholas P. Ross"
  ],
  "comment": "26 pages, MNRAS, in press",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "Spectropolarimetry is a powerful technique that has provided critical support for the geometric unification model of local active galactic nuclei. In this paper, we present optical (rest-frame UV) Keck spectropolarimetry of five luminous obscured (Type 2) and extremely red quasars (ERQs) at z~2.5. Three objects reach polarization fractions of >10% in the continuum. We propose a model in which dust scattering is the dominant scattering and polarization mechanism in our targets, though electron scattering cannot be completely excluded. Emission lines are polarized at a lower level than is the continuum. This suggests that the emission-line region exists on similar spatial scales as the scattering region. In three objects we detect an intriguing 90 degree swing in the polarization position angle as a function of line-of-sight velocity in the emission lines of Ly-alpha, CIV and NV. We interpret this phenomenon in the framework of a geometric model with an equatorial dusty scattering region in which the material is outflowing at several thousand km/sec. Emission lines may also be scattered by dust or resonantly. This model explains several salient features of observations by scattering on scales of a few tens of pc. Our observations provide a tantalizing view of the inner region geometry and kinematics of high-redshift obscured and extremely red quasars. Our data and modeling lend strong support for toroidal obscuration and powerful outflows on the scales of the UV emission-line region, in addition to the larger scale outflows inferred previously from the optical emission-line kinematics.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2018-06-26T18:00:00.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "high redshift",
      "spectropolarimetry",
      "emission lines",
      "objects reach polarization fractions",
      "scattering"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 26,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}