Light-cone averaging in cosmology: formalism and applications
Abstract
We present a general gauge invariant formalism for defining cosmological averages that are relevant for observations based on light-like signals. Such averages involve either null hypersurfaces corresponding to a family of past light-cones or compact surfaces given by their intersection with timelike hypersurfaces. Generalized Buchert-Ehlers commutation rules for derivatives of these light-cone averages are given. After introducing some adapted "geodesic light-cone" coordinates, we give explicit expressions for averaging the redshift to luminosity-distance relation and the so-called "redshift drift" in a generic inhomogeneous Universe.
Cite
@article{arxiv.1104.1167,
title = {Light-cone averaging in cosmology: formalism and applications},
author = {M. Gasperini and G. Marozzi and F. Nugier and G. Veneziano},
journal= {arXiv preprint arXiv:1104.1167},
year = {2011}
}
Comments
20 pages, 2 figures. Comments and references added, typos corrected. Version accepted for publication in JCAP