2008/01/31 by Wayne Hu · 3 citations
Physics and Astronomy · #Advanced Differential Geometry Research #Cosmology and Gravitation Theories #Radio Astronomy Observations and Technology #astro-ph
paper · pdf · doi:10.1103/physrevd.77.103524
published as Phys.Rev.D77:103524,2008 · 11 pages, 8 figures, changes reflect PRD published version, several typos corrected thanks to Wenjuan Fang
arxiv created 2008/04/03 · openalex publication_date 2008/05/27 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We extend the covariant, parametrized post-Friedmann treatment of cosmic acceleration from modified gravity to an arbitrary admixture of matter, radiation, relativistic components, and spatial curvature. This generalization facilitates the adaptation of Einstein-Boltzmann codes for solving cosmic microwave background and matter perturbations in the linear regime. We use such a code to study the effect of metric evolution on the cosmic microwave background through the integrated Sachs-Wolfe effect. We discuss the ability of modified gravity to alter the low multipole spectrum, including lowering the power in the quadrupole. From a principal component description of the primary metric ratio parameter, we obtain general constraints from the Wilkinson Microwave Anisotropy Probe on modified gravity models of the acceleration.