2019/11/30 by Benedikt Eggemeier, Javier Redondo, Klaus Dolag +2 · 1 citation
Physics and Astronomy · #astro-ph.CO
paper · pdf · doi:10.1103/physrevlett.125.041301
published as Phys. Rev. Lett. 125, 041301 (2020) · 8 pages, 6 figures, accepted by PRL
arxiv created 2020/07/21 · arxiv updated 2020/07/22
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 ∼ 0.75 at redshift z=100.