{
  "id": "1511.04457",
  "version": "v1",
  "published": "2015-11-13T21:05:17.000Z",
  "updated": "2015-11-13T21:05:17.000Z",
  "title": "Constraining Gravity at the Largest Scales through CMB Lensing and Galaxy Velocities",
  "authors": [
    "Anthony R. Pullen",
    "Shadab Alam",
    "Siyu He",
    "Shirley Ho"
  ],
  "comment": "11 pages, 9 figures, to be submitted to MNRAS",
  "categories": [
    "astro-ph.CO"
  ],
  "abstract": "We demonstrate a new method to constrain gravity on the largest cosmological scales by combining measurements of cosmic microwave background (CMB) lensing and the galaxy velocity field. $E_G$ is a statistic, constructed from a gravitational lensing tracer and a measure of velocities such as redshift-space distortions (RSD), that can discriminate between gravity models while being independent of clustering bias and $\\sigma_8$. While traditionally, the lensing field for $E_G$ has been probed through galaxy lensing, CMB lensing has been proposed as a more robust tracer of the lensing field for $E_G$ at higher redshifts while avoiding intrinsic alignments. We perform the largest-scale measurement of $E_G$ ever, up to 150 Mpc/$h$, by cross-correlating the Planck CMB lensing map with the Sloan Digital Sky Survey III (SDSS-III) CMASS galaxy sample and combining this with our measurement of the CMASS auto-power spectrum and the RSD parameter $\\beta$. We report $E_G(z=0.57)=0.243\\pm0.060$ (stat) $\\pm0.013$ (sys), a measurement in tension with the general relativity prediction at a level of 2.6$\\sigma$. Upcoming surveys, which will provide an order-of-magnitude reduction in statistical errors, can significantly constrain alternative gravity models when combined with better control of systematics.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2015-11-13T21:05:17.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "cmb lensing",
      "galaxy velocity",
      "largest scales",
      "constraining gravity",
      "sloan digital sky survey"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 11,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2015arXiv151104457P",
      "inspire": 1404821
    }
  }
}