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Main Authors: Eggemeier, Benedikt, Anilkumar, Ananthu Krishnan, Dolag, Klaus
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2402.18221
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author Eggemeier, Benedikt
Anilkumar, Ananthu Krishnan
Dolag, Klaus
author_facet Eggemeier, Benedikt
Anilkumar, Ananthu Krishnan
Dolag, Klaus
contents We identify axion miniclusters collapsing in the radiation-dominated era and follow them to redshift $z=99$ with N-body simulations. We find that the majority of the densest miniclusters end up in the center of larger minicluster halos at late times. Soon after their formation, the miniclusters exhibit NFW profiles but they subsequently develop a steeper inner slope approaching $ρ\sim r^{-2}$ on small scales. Using the so far most highly resolved axion structure formation simulation with $2048^3$ particles we examine the structure of previously studied minicluster halos. While the density profiles of their subhalos are NFW-like we confirm that a modified NFW profile with a steeper inner slope provides a better description for minicluster halos with masses above $\sim 10^{-12}\,M_\odot$. We show that miniclusters with a higher central density might be in contrast to pure NFW halos dense enough to induce gravitational microlensing. Likewise, more compact minicluster halos will have immediate implications for direct and indirect axion detection.
format Preprint
id arxiv_https___arxiv_org_abs_2402_18221
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Evidence for axion miniclusters with an increased central density
Eggemeier, Benedikt
Anilkumar, Ananthu Krishnan
Dolag, Klaus
Cosmology and Nongalactic Astrophysics
We identify axion miniclusters collapsing in the radiation-dominated era and follow them to redshift $z=99$ with N-body simulations. We find that the majority of the densest miniclusters end up in the center of larger minicluster halos at late times. Soon after their formation, the miniclusters exhibit NFW profiles but they subsequently develop a steeper inner slope approaching $ρ\sim r^{-2}$ on small scales. Using the so far most highly resolved axion structure formation simulation with $2048^3$ particles we examine the structure of previously studied minicluster halos. While the density profiles of their subhalos are NFW-like we confirm that a modified NFW profile with a steeper inner slope provides a better description for minicluster halos with masses above $\sim 10^{-12}\,M_\odot$. We show that miniclusters with a higher central density might be in contrast to pure NFW halos dense enough to induce gravitational microlensing. Likewise, more compact minicluster halos will have immediate implications for direct and indirect axion detection.
title Evidence for axion miniclusters with an increased central density
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2402.18221