Power spectrum of electron number density perturbations at cosmological recombination epoch

TL;DR

This paper calculates the power spectrum of free electron density perturbations during cosmological recombination, revealing they are significantly larger than baryon matter perturbations on large scales and analyzing their dependence on cosmological parameters.

Contribution

It provides the first detailed calculation of the electron density perturbation power spectrum during recombination and compares it to baryon matter perturbations, highlighting their amplitude differences.

Findings

Electron perturbations exceed baryon matter perturbations by a factor of 17 on large scales.

The ratio of electron to baryon perturbations varies from 16 to 18 across acoustic peaks.

The dependence of these ratios on cosmological parameters is analyzed.

Abstract

The power spectrum of number density perturbations of free electrons is obtained for the epoch of cosmological recombination of hydrogen. It is shown that amplitude of the electron perturbations power spectrum of scales larger than acoustic horizon exceeds by factor of 17 the amplitude of baryon matter density ones (atoms and ions of hydrogen and helium). In the range of the first and second acoustic peaks such relation is 18, in the range of the third one 16. The dependence of such relations on cosmological parameters is analysed too.