{
  "id": "1803.07473",
  "version": "v1",
  "published": "2018-03-20T15:08:48.000Z",
  "updated": "2018-03-20T15:08:48.000Z",
  "title": "Test of the cosmological principle by means of CMB multipole vectors for $l \\leq 50$",
  "authors": [
    "Marvin Pinkwart",
    "Dominik J. Schwarz"
  ],
  "comment": "24 pages, 38 figures; Uses REVTeX 4.1; Files containing multipole vectors are provided at https://github.com/MPinkwart/MPV-files-Pinkwart-Schwarz",
  "categories": [
    "astro-ph.CO",
    "gr-qc",
    "hep-ph"
  ],
  "abstract": "The statistical cosmological principle states that observables on the celestial sphere are sampled from a rotationally invariant distribution. Previously certain large scale anomalies which violate this principle have been found, for example an alignment of the lowest multipoles with the cosmic dipole direction. In this work we continue the investigation of possible violations of statistical isotropy using multipole vectors which represent a convenient tool for this purpose. We investigate all four full-sky foreground-cleaned maps from the Planck 2015 release with respect to four meaningful physical directions using computationally cheap statistics that have a simple geometric interpretation. We find that the SEVEM map deviates strongly from all the other cleaned maps and should not be used for cosmological full-sky analyses of statistical isotropy. The other three maps COMMANDER, NILC and SMICA show a remarkably consistent behavior. On the largest angular scales, $l \\leq 5$, as well as on intermediate scales, $l=20,21,22,23,24$, all of them are unusually correlated with the cosmic dipole direction. These scales coincide with the scales on which the angular power spectrum deviates from the Planck 2015 best-fit $\\Lambda$CDM model. In the range $2 \\leq l \\leq 50$ as a whole there is no unusual behavior visible globally. We do not find abnormal intra-multipole correlation, i.e. correlation of multipole vectors inside a given multipole without reference to any outer direction, but we observe a lack of variance in intra-multipole alignment statistics. The possibility of a connection between galactic center foreground and previously reported parity anomalies is discussed.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2018-03-20T15:08:48.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "cmb multipole vectors",
      "cosmological principle",
      "cosmic dipole direction",
      "angular power spectrum deviates",
      "large scale anomalies"
    ],
    "tags": [
      "github project"
    ],
    "note": {
      "typesetting": "RevTeX",
      "pages": 24,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}