{
  "id": "1506.07182",
  "version": "v1",
  "published": "2015-06-23T20:01:18.000Z",
  "updated": "2015-06-23T20:01:18.000Z",
  "title": "Compact Radio Sources within 30\" of Sgr A*: Proper Motions, Stellar Winds and the Accretion Rate onto Sgr A*",
  "authors": [
    "F. Yusef-Zadeh",
    "H. Bushouse",
    "R. Schödel",
    "M. Wardle",
    "W. Cotton",
    "D. A. Roberts",
    "F. Nogueras-Lara",
    "E. Gallego-Cano"
  ],
  "comment": "30 pages, 4 figures, ApJ (in press)",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "Recent broad-band 34 and 44 GHz radio continuum observations of the Galactic center have revealed 41 massive stars identified with near-IR counterparts, as well as 44 proplyd candidates within 30\" of Sgr A*. Radio observations obtained in 2011 and 2014 have been used to derive proper motions of eight young stars near Sgr A*. The accuracy of proper motion estimates based on near-IR observations by Lu et al. and Paumard et al. have been investigated by using their proper motions to predict the 2014 epoch positions of near-IR stars and comparing the predicted positions with those of radio counterparts in the 2014 radio observations. Predicted positions from Lu et al. show an rms scatter of 6 mas relative to the radio positions, while those from Paumard et al. show rms residuals of 20 mas, which is mainly due to uncertainties in the IR-based proper motions. Under the assumption of homogeneous ionized winds, we also determine the mass-loss rates of 11 radio stars, finding rates that are on average $\\sim$2 times smaller than those determined from model atmosphere calculations and near-IR data. Clumpiness of ionized winds would reduce the mass loss rate of WR and O stars by additional factors of 3 and 10, respectively. One important implication of this is a reduction in the expected mass accretion rate onto Sgr A* from stellar winds by nearly an order of magnitude to a value of few$\\times10^{-7}$ \\msol\\ yr$^{-1}$. Finally, we present the positions of 318 compact 34.5 GHz radio sources within 30\\arcs\\ of Sgr A*. At least 45 of these have stellar counterparts in the near-IR $K_s$ (2.18 $\\mu$m) and $L'$ (3.8$\\mu$m) bands.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2015-06-23T20:01:18.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "proper motion",
      "compact radio sources",
      "accretion rate",
      "stellar winds",
      "ghz radio continuum observations"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 30,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}