Cosmic Recombination in the Presence of Primordial Magnetic Fields

Fuente: arXiv
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Main Authors: Jedamzik, Karsten, Abel, Tom, Ali-Haimoud, Yacine
Format: Preprint
Published: 2023
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author Jedamzik, Karsten
Abel, Tom
Ali-Haimoud, Yacine
author_facet Jedamzik, Karsten
Abel, Tom
Ali-Haimoud, Yacine
contents Primordial magnetic fields (PMFs) may explain observations of magnetic fields on extragalactic scales. They are most cleanly constrained by measurements of cosmic microwave background radiation (CMB) anisotropies. Their effects on cosmic recombination may even be at the heart of the resolution of the Hubble tension. We present the most detailed analysis of the effects of PMFs on cosmic recombination to date. To this end we extend the public magneto-hydrodynamic code {\sl ENZO} with a new cosmic recombination routine, Monte-Carlo simulations of Lyman-$α$ photon transport, and a Compton drag term in the baryon momentum equation. The resulting code allows us, for the first time, to realistically predict the impact of PMFs on the cosmic ionization history and the clumping of baryons during cosmic recombination. Our results identify the importance of mixing of Lyman-$α$ photons between overdense- and underdense- regions for small PMF strength. This mixing speeds up recombination beyond the speed-up due to clumping. We also investigate the effects of pecuilar flows on the recombination rate and find it to be small for small PMF strengths. For non-helical PMFs with a Batchelor spectrum we find a surprising dependency of results on ultra-violet magnetic modes. We further show that the increase in the ionization fraction at low redshift by hydrodynamic baryon heating due to PMF dissipation is completely compensated by the faster recombination from baryon clumping. The present study shall serve as a theoretical foundation for a future precise comparison of recombination with PMFs to CMB data.
format Preprint
id arxiv_https___arxiv_org_abs_2312_11448
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Cosmic Recombination in the Presence of Primordial Magnetic Fields
Jedamzik, Karsten
Abel, Tom
Ali-Haimoud, Yacine
Cosmology and Nongalactic Astrophysics
High Energy Physics - Phenomenology
Primordial magnetic fields (PMFs) may explain observations of magnetic fields on extragalactic scales. They are most cleanly constrained by measurements of cosmic microwave background radiation (CMB) anisotropies. Their effects on cosmic recombination may even be at the heart of the resolution of the Hubble tension. We present the most detailed analysis of the effects of PMFs on cosmic recombination to date. To this end we extend the public magneto-hydrodynamic code {\sl ENZO} with a new cosmic recombination routine, Monte-Carlo simulations of Lyman-$α$ photon transport, and a Compton drag term in the baryon momentum equation. The resulting code allows us, for the first time, to realistically predict the impact of PMFs on the cosmic ionization history and the clumping of baryons during cosmic recombination. Our results identify the importance of mixing of Lyman-$α$ photons between overdense- and underdense- regions for small PMF strength. This mixing speeds up recombination beyond the speed-up due to clumping. We also investigate the effects of pecuilar flows on the recombination rate and find it to be small for small PMF strengths. For non-helical PMFs with a Batchelor spectrum we find a surprising dependency of results on ultra-violet magnetic modes. We further show that the increase in the ionization fraction at low redshift by hydrodynamic baryon heating due to PMF dissipation is completely compensated by the faster recombination from baryon clumping. The present study shall serve as a theoretical foundation for a future precise comparison of recombination with PMFs to CMB data.
title Cosmic Recombination in the Presence of Primordial Magnetic Fields
topic Cosmology and Nongalactic Astrophysics
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2312.11448