{
  "id": "2310.06831",
  "version": "v1",
  "published": "2023-10-10T17:58:04.000Z",
  "updated": "2023-10-10T17:58:04.000Z",
  "title": "Impacts of the Local arm on the local circular velocity inferred from the Gaia DR3 young stars in the Milky Way",
  "authors": [
    "Aisha S. Almannaei",
    "Daisuke Kawata",
    "Junichi Baba",
    "Jason A. S. Hunt",
    "George Seabroke",
    "Ziyang Yan"
  ],
  "comment": "13 pages, 11 figures",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "A simple one-dimensional axisymmetric disc model is applied to the kinematics of OB stars near the Sun obtained from Gaia DR3 catalogue. The model determines the 'local centrifugal speed' $V_\\mathrm{c}(R_{0})$ - defined as the circular velocity in the Galactocentric rest frame, where the star would move in a near-circular orbit if the potential is axisymmetric with the local potential of the Galaxy. We find that the $V_\\mathrm{c}(R_{0})$ values and their gradient vary across the selected region of stars within the solar neighbourhood. By comparing with an N-body/hydrodynamic simulation of a Milky Way-like galaxy, we find that the kinematics of the young stars in the solar neighbourhood is affected by the Local arm, which makes it difficult to measure $V_\\mathrm{c}(R_{0})$. However, from the resemblance between the observational data and the simulation, we suggest that the known rotational velocity gap between the Coma Bernices and Hyades-Pleiades moving groups could be driven by the co-rotation resonance of the Local arm, which can be used to infer the azimuthally averaged circular velocity. We find that $V_\\mathrm{c}(R)$ obtained from the $\\mathrm{D}<2$ kpc sample is well matched with this gap at the position of the Local arm. Hence, we argue that our results from the $\\mathrm{D}<2$ kpc sample, $V_\\mathrm{c}(R_{0})= 233.95\\pm2.24$ km $\\mathrm{s}^{-1}$, is close to the azimuthally averaged circular velocity rather than the local centrifugal speed, which is influenced by the presence of the Local arm.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2023-10-10T17:58:04.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "local arm",
      "gaia dr3 young stars",
      "local circular velocity",
      "milky way",
      "azimuthally averaged circular velocity"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 13,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}