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arXiv · 1911.09417

First Simulations of Axion Minicluster Halos

Benedikt Eggemeier·Javier Redondo·Klaus Dolag·Jens C. Niemeyer·Alejandro Vaquero
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Abstract

We study the gravitational collapse of axion dark matter fluctuations in the post-inflationary scenario, so-called axion miniclusters, with N-body simulations. Largely confirming theoretical expectations, overdensities begin to collapse in the radiation-dominated epoch and form an early distribution of miniclusters with masses up to $10^{-12}\,M_\odot$. After matter-radiation equality, ongoing mergers give rise to a steep power-law distribution of minicluster halo masses. The density profiles of well-resolved halos are NFW-like to good approximation. The fraction of axion dark matter in these bound structures is $\sim 0.75$ at redshift $z=100$.

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Benedikt Eggemeier, Javier Redondo, Klaus Dolag, Jens C. Niemeyer, Alejandro Vaquero. 2019-11-21. First Simulations of Axion Minicluster Halos. https://doi.org/10.1103/physrevlett.125.041301

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