Extreme Axions Unveiled: a Novel Fluid Approach for Cosmological Modeling

Fuente: arXiv
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Main Authors: Winch, Harrison, Hlozek, Renee, Marsh, David J. E., Grin, Daniel, Rogers, Keir
Format: Preprint
Published: 2023
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author Winch, Harrison
Hlozek, Renee
Marsh, David J. E.
Grin, Daniel
Rogers, Keir
author_facet Winch, Harrison
Hlozek, Renee
Marsh, David J. E.
Grin, Daniel
Rogers, Keir
contents Axion-like particles (ALPs) are a well-motivated dark matter candidate that solve some of the problems in the clustering of large scale structure in cosmology. ALPs are often described by a simplified quadratic potential to specify the dynamics of the axion field, and are included in cosmological analysis codes using a modified fluid prescription. In this paper we consider the extreme axion: a version of the axion with a high initial field angle that produces an enhancement (rather than a suppression) of structure on small scales around the Jeans length, which can be probed by measurements of clustering such as the eBOSS DR14 Ly-$α$ forest. We present a novel method of modeling the extreme axion as a cosmological fluid, combining the Generalized Dark Matter model with the effective fluid approach presented in the \texttt{axionCAMB} software, as well as implementing a series of computational innovations to efficiently simulate the extreme axions. We find that for axion masses between $10^{-23} \mathrm{\ eV} \lesssim m_\mathrm{ax} \lesssim 10^{-22.5} \mathrm{\ eV}$, constraints on the axion fraction imposed by the eBOSS DR14 Ly-$α$ forest can be significantly weakened by allowing them to be in the form of extreme axions with a starting angle between $π- 10^{-1} \lesssim θ_i \lesssim π- 10^{-2}$. This work motivates and enables a more robust hydrodynamical analysis of extreme axions in order to compare them to high-resolution Ly-$α$ forest data in the future.
format Preprint
id arxiv_https___arxiv_org_abs_2311_02052
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Extreme Axions Unveiled: a Novel Fluid Approach for Cosmological Modeling
Winch, Harrison
Hlozek, Renee
Marsh, David J. E.
Grin, Daniel
Rogers, Keir
Cosmology and Nongalactic Astrophysics
High Energy Physics - Phenomenology
Axion-like particles (ALPs) are a well-motivated dark matter candidate that solve some of the problems in the clustering of large scale structure in cosmology. ALPs are often described by a simplified quadratic potential to specify the dynamics of the axion field, and are included in cosmological analysis codes using a modified fluid prescription. In this paper we consider the extreme axion: a version of the axion with a high initial field angle that produces an enhancement (rather than a suppression) of structure on small scales around the Jeans length, which can be probed by measurements of clustering such as the eBOSS DR14 Ly-$α$ forest. We present a novel method of modeling the extreme axion as a cosmological fluid, combining the Generalized Dark Matter model with the effective fluid approach presented in the \texttt{axionCAMB} software, as well as implementing a series of computational innovations to efficiently simulate the extreme axions. We find that for axion masses between $10^{-23} \mathrm{\ eV} \lesssim m_\mathrm{ax} \lesssim 10^{-22.5} \mathrm{\ eV}$, constraints on the axion fraction imposed by the eBOSS DR14 Ly-$α$ forest can be significantly weakened by allowing them to be in the form of extreme axions with a starting angle between $π- 10^{-1} \lesssim θ_i \lesssim π- 10^{-2}$. This work motivates and enables a more robust hydrodynamical analysis of extreme axions in order to compare them to high-resolution Ly-$α$ forest data in the future.
title Extreme Axions Unveiled: a Novel Fluid Approach for Cosmological Modeling
topic Cosmology and Nongalactic Astrophysics
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2311.02052