{
  "id": "2307.13729",
  "version": "v1",
  "published": "2023-07-25T18:00:02.000Z",
  "updated": "2023-07-25T18:00:02.000Z",
  "title": "Nine lensed quasars and quasar pairs discovered through spatially-extended variability in Pan-STARRS",
  "authors": [
    "Frédéric Dux",
    "Cameron Lemon",
    "Frédéric Courbin",
    "Favio Neira",
    "Timo Anguita",
    "Aymeric Galan",
    "Sam Kim",
    "Maren Hempel",
    "Angela Hempel",
    "Régis Lachaume"
  ],
  "comment": "11 pages, 7 figures",
  "categories": [
    "astro-ph.GA",
    "astro-ph.CO"
  ],
  "abstract": "We present the proof-of-concept of a method to find strongly lensed quasars using their spatially-extended photometric variability through difference imaging in cadenced imaging survey data. We apply the method to Pan-STARRS, starting with an initial selection of 14 107 Gaia multiplets with quasar-like infrared colours from WISE. We identify 229 candidates showing notable spatially-extended variability during the Pan-STARRS survey period. These include 20 known lenses, alongside an additional 12 promising candidates for which we obtain long-slit spectroscopy follow-up. This process results in the confirmation of four doubly lensed quasars, four unclassified quasar pairs and one projected quasar pair. Only three are pairs of stars or quasar+star projections, the false positive rate is thereby 25%. The lenses have separations between 0.81\" and 1.24\" and source redshifts between z = 1.47 and z = 2.46. Three of the unclassified quasar pairs are promising dual quasars candidates with separations ranging from 6.6 to 9.3 kpc. We expect that this technique will be a particularly efficient way to select lensed variables in the upcoming Rubin-LSST, which will be crucial given the expected limitations for spectroscopic follow-up",
  "revisions": [
    {
      "version": "v1",
      "updated": "2023-07-25T18:00:02.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "lensed quasars",
      "unclassified quasar pairs",
      "showing notable spatially-extended variability",
      "long-slit spectroscopy follow-up",
      "pan-starrs survey period"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 11,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}