{
  "id": "1610.09385",
  "version": "v1",
  "published": "2016-10-28T20:00:27.000Z",
  "updated": "2016-10-28T20:00:27.000Z",
  "title": "Improved Dynamical Constraints on the Mass of the central Black Hole in NGC 404",
  "authors": [
    "Dieu D. Nguyen",
    "Anil C. Seth",
    "Mark den Brok",
    "Nadine Neumayer",
    "Michele Cappellari",
    "Aaron J. Barth",
    "Nelson Caldwell",
    "Benjamin F. Williams",
    "Breanna Binder"
  ],
  "comment": "23 papes, 16 figures, 6 tables, After referee's report 2016",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We explore the nucleus of the nearby 10$^9$\\Msun~early-type galaxy (ETGs), NGC~404, using \\emph{Hubble Space Telescope} (\\hst)/STIS spectroscopy and WFC3 imaging. We first present evidence for nuclear variability in UV, optical, and infrared filters over a time period of 15~years. This variability adds to the already substantial evidence for an accreting black hole at the center of NGC~404. We then redetermine the dynamical black hole mass in NGC~404 including modeling of the nuclear stellar populations. We combine \\hst/STIS spectroscopy with WFC3 images to create a local color--\\ml~relation derived from stellar population modeling of the STIS data. We then use this to create a mass model for the nuclear region. We use Jeans modeling to fit this mass model to adaptive optics (AO) stellar kinematic observations from Gemini/NIFS. From our stellar dynamical modeling, we find a 3$\\sigma$ upper limit on the black hole mass of $1.5\\times10^5$\\Msun. Given the accretion evidence for a black hole, this upper limit makes NGC~404 the lowest mass central black hole with dynamical mass constraints. We find that the kinematics of H$_2$ emission line gas show evidence for non-gravitational motions preventing the use of gas dynamical modeling to constrain the black hole mass. Our stellar population modeling also reveals that the central, counter-rotating region of the nuclear cluster is dominated by $\\sim$1~Gyr old populations.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2016-10-28T20:00:27.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "black hole mass",
      "dynamical constraints",
      "lowest mass central black hole",
      "mass model",
      "stellar population modeling"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}