Cosmological perturbations at second order and recombination perturbed
- School of Natural Sciences, Institute for Advanced Study, Olden Lane, Princeton, NJ 08540 (United States)
- Center for Astrophysics, Harvard University, 60 Garden Street, Cambridge, MA 02138 (United States)
- Jefferson Physical Laboratory, Harvard University, 17 Oxford Street, Cambridge, MA 02138 (United States)
We derive the full set of second-order equations governing the evolution of cosmological perturbations, including the effects of the first-order electron number density perturbations, δ{sub e}. We provide a detailed analysis of the perturbations to the recombination history of the universe and show that a perturbed version of the Peebles effective 3-level atom is sufficient for obtaining the evolution of δ{sub e} for comoving wavenumbers smaller than 1 Mpc{sup −1}. We calculate rigorously the perturbations to the Lyα escape probability and show that to a good approximation it is governed by the local baryon velocity divergence. For modes longer than the photon diffusion scale, we find that δ{sub e} is enhanced during recombination by a factor of roughly 5 relative to other first-order quantities sourcing the CMB anisotropies at second order. Using these results, in a companion paper we calculate the CMB bispectrum generated during recombination.
- OSTI ID:
- 22273239
- Journal Information:
- Journal of Cosmology and Astroparticle Physics, Vol. 2009, Issue 08; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
- Country of Publication:
- United States
- Language:
- English
Similar Records
CMB anisotropies at second order III: bispectrum from products of the first-order perturbations
Non-gaussianities from perturbing recombination