{
  "id": "1902.09569",
  "version": "v1",
  "published": "2019-02-25T19:09:11.000Z",
  "updated": "2019-02-25T19:09:11.000Z",
  "title": "More than just a wrinkle: A wave-like pattern in radial velocity vs. angular momentum from Gaia Data",
  "authors": [
    "Jennifer Friske",
    "Ralph Schönrich"
  ],
  "comment": "10 pages, 12 figures, submitted to MNRAS",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We present a newly found wave--like pattern in mean Galactocentric radial velocity U_g vs. guiding centre radius R_g or angular momentum L_z of stars in the RV subsample of Gaia DR2. The short-wave pattern has a wavelength of order 1.2 kpc in R_g or 285 kpc km/s in L_z. The pattern shows only weak changes with Galactocentric radius R and little change in strength in particular with the vertical energy E_z of the stars or respectively the distance to the Galactic plane |z|. The pattern is to first order symmetric around the plane, i.e. has no significant odd terms in z. There is weak phase shift with the pattern moving towards slightly lower L_z (i.e. trailing) with |z| and E_z. However, we observe a highly significant phase shift in Galactic azimuth phi, which is different for different peaks. The peak around L_z ~ 2100 kpc km/s shows weak/uncertain change and shifts by of order dL_z/d phi ~ (97 +/- 32) kpc km/s/rad, while the rest of the pattern shows a clearly detectable shift of ~ (200 +/- 22) kpc km/s/rad. If we consider all peaks to belong to the same pattern, this would suggest a wavenumber m = 4. We further find that the wave-like pattern in U_g appears to be related to the W vs. L_z pattern detected in Gaia DR1. A comparison of the U_g-L_z wave pattern with changes of U_g vs. R, which have been previously discussed, suggests that the latter can be understood as just the U_g-L_z pattern washed out by blurring (i.e. orbital excursions around their guiding-centre) of disc stars.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2019-02-25T19:09:11.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "angular momentum",
      "wave-like pattern",
      "gaia data",
      "kpc km/s/rad",
      "mean galactocentric radial velocity"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 10,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}