{
  "id": "2006.16355",
  "version": "v1",
  "published": "2020-06-29T20:18:48.000Z",
  "updated": "2020-06-29T20:18:48.000Z",
  "title": "Gaia and Hubble unveil the kinematics of stellar populations in the Type II globular clusters ω Centauri and M 22",
  "authors": [
    "G. Cordoni",
    "A. P. Milone",
    "A. F. Marino",
    "G. S. Da Costa",
    "E. Dondoglio",
    "H. Jerjen",
    "E. P. Lagioia",
    "A. Mastrobuono-Battisti",
    "J. E. Norris",
    "M. Tailo",
    "D. Yong"
  ],
  "comment": "24 pages, 13 figures, accepted for publication in ApJ",
  "categories": [
    "astro-ph.SR",
    "astro-ph.GA"
  ],
  "abstract": "The origin of multiple stellar populations in Globular Clusters (GCs) is one of the greatest mysteries of modern stellar astrophysics. N-body simulations suggest that the present-day dynamics of GC stars can constrain the events that occurred at high redshift and led to the formation of multiple populations. Here, we combine multi-band photometry from the Hubble Space Telescope (HST) and ground-based facilities with HST and Gaia Data Release 2 proper motions to investigate the spatial distributions and the motions in the plane of the sky of multiple populations in the type II GCs NGC 5139 ($\\omega\\,$Centauri) and NGC 6656 (M 22). We first analyzed stellar populations with different metallicities. Fe-poor and Fe-rich stars in M 22 share similar spatial distributions and rotation patterns and exhibit similar isotropic motions. Similarly, the two main populations with different iron abundance in $\\omega\\,$Centauri share similar ellipticities and rotation patterns. When analyzing different radial regions, we find that the rotation amplitude decreases from the center towards the external regions. Fe-poor and Fe-rich stars of $\\omega\\,$Centauri are radially anisotropic in the central region and show similar degrees of anisotropy. We also investigate the stellar populations with different light-element abundances and find that their N-rich stars exhibit higher ellipticity than N-poor stars. In $\\omega\\,$Centauri Centauri both stellar groups are radially anisotropic. Interestingly, N-rich, Fe-rich stars exhibit different rotation patterns than N-poor stars with similar metallicities. The stellar populations with different nitrogen of M 22 exhibit similar rotation patterns and isotropic motions. We discuss these findings in the context of the formation of multiple populations.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-06-29T20:18:48.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "stellar populations",
      "globular clusters",
      "rotation patterns",
      "hubble unveil",
      "multiple populations"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 24,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}