{
  "id": "astro-ph/0610794",
  "version": "v2",
  "published": "2006-10-26T15:34:29.000Z",
  "updated": "2007-06-06T11:28:39.000Z",
  "title": "Constraints on f(R) Cosmology in the Palatini Formalism",
  "authors": [
    "Baojiu Li",
    "K. C. Chan",
    "M. -C. Chu"
  ],
  "comment": "9 pages, 7 figures. Modified version to appear in Physical Review D",
  "journal": "Phys.Rev.D76:024002,2007",
  "doi": "10.1103/PhysRevD.76.024002",
  "categories": [
    "astro-ph",
    "gr-qc"
  ],
  "abstract": "In this work we derive the covariant and gauge invariant perturbation equations in general theories of $f(R)$ gravity in the Palatini formalism to linear order and calculate the cosmic microwave background (CMB) and matter power spectra for an extensively discussed model, $f(R) = R + \\alpha(-R)^\\beta$, which is a possible candidate for the late-time cosmic accelerating expansion found recently. These spectra are discussed and found to be sensitively dependent on the value of $\\beta$. We are thus able to make stringent constraints on $\\beta$ from cosmological data on CMB and matter power spectra: The three-year Wilkinson Microwave Anisotropy Probe (WMAP) data alone gives a constraint $|\\beta| \\lesssim \\mathcal{O}(10^{{-3}})$ while the joint WMAP, Supernova Lagacy Survey (SNLS) and Sloan Digital Sky Survey (SDSS) data sets tightens this to $\\beta \\sim \\mathcal{O}(10^{{-6}})$, about an order of magnitude more stringent than the constraint from SDSS data alone, which makes this model practically indistinguishable from the standard $\\Lambda\\mathrm{CDM}$ paradigm.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2007-06-06T11:28:39.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "98.65.-r",
      "98.70.Vc",
      "04.50.+h"
    ],
    "keywords": [
      "palatini formalism",
      "constraint",
      "matter power spectra",
      "three-year wilkinson microwave anisotropy probe",
      "gauge invariant perturbation equations"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Phys. Rev. D"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 9,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 729997
    }
  }
}