The Impact of Stochastic Primordial Magnetic Fields on the Scalar Contribution to Cosmic Microwave Background Anisotropies

TL;DR

This paper investigates how stochastic primordial magnetic fields influence the scalar component of CMB anisotropies and matter power spectrum, providing precise initial conditions and analytical expressions for their effects.

Contribution

It introduces accurate initial conditions and exact formulas for the energy density and Lorentz force of primordial magnetic fields with power-law spectra, enhancing modeling precision.

Findings

Primordial magnetic fields affect CMB temperature and polarization spectra.

The impact depends on the magnetic field parameters and spectral properties.

The study offers detailed dependence of CMB spectra on magnetic field characteristics.

Abstract

We study the impact of a stochastic background of primordial magnetic fields on the scalar contribution of CMB anisotropies and on the matter power spectrum. We give the correct initial conditions for cosmological perturbations and the exact expressions for the energy density and Lorentz force associated to the stochastic background of primordial magnetic fields, given a power-law for their spectra cut at a damping scale. The dependence of the CMB temperature and polarization spectra on the relevant parameters of the primordial magnetic fields is illustrated.