The tension of cosmological magnetic fields as a contribution to dark energy

TL;DR

This paper explores how cosmological magnetic fields could contribute to dark energy, proposing a model tested against supernova and galaxy age data that fits well with observed cosmological parameters.

Contribution

It introduces a novel model where magnetic fields influence the Universe's expansion, providing constraints based on observational data.

Findings

Magnetic fields can mimic dark energy effects in cosmological models.

Best-fit parameters suggest a magnetic field contribution of about 3%.

The model aligns with current supernova and galaxy age observations.

Abstract

We propose that cosmological magnetic fields generated in regions of finite spatial dimensions may manifest themselves in the global dynamics of the Universe as `dark energy'. We test our model in the context of spatially flat cosmological models by assuming that the Universe contains non-relativistic matter $\rho_m\propto \alpha^{-3}$, dark energy $\rho_{Q}\propto \alpha^{-3(1+w)}$, and an extra fluid with $\rho_{B} \propto \alpha^{n-3}$ that corresponds to the magnetic field. We place constraints on the main cosmological parameters of our model by combining the recent supernovae type Ia data and the differential ages of passively evolving galaxies. In particular, we find that the model which best reproduces the observational data when $\Omega_m=0.26$ is one with $\Omega_{B}\simeq 0.03$, $n\simeq 7.68$, $\Omega_{Q}\simeq 0.71$ and $w\simeq -0.8$.