Year: 2009
Type: article
Abstract: The constraints on departures from general relativity (GR) at cosmological length scales due to cosmic microwave background (CMB) data are discussed. The departure from GR is measured by the ratio, parametrized as $1+{\ensuremath{\varpi}}_{0}(1+z{)}^{\ensuremath{-}S}$, between the gravitational potentials conventionally appearing in the geodesic equation and the Poisson equation. Current CMB data indicate ${\ensuremath{\varpi}}_{0}={1.67}_{\ensuremath{-}1.87}^{+3.07}$ at the $2\ensuremath{\sigma}$ confidence level, while $S$ remains unconstrained. The departure from GR affects the lensing conversion of E-mode into B-mode polarization. Hence, the lensing measurements from CMBpol alone should be able to improve the constraint to ${\ensuremath{\varpi}}_{0}<0.52$ ($2\ensuremath{\sigma}$) for a fiducial ${\ensuremath{\varpi}}_{0}=0$ model independent of $S$.
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2008016657