Halo abundance and assembly history with extreme-axion wave dark matter at z >= 4
Journal
Monthly Notices of the Royal Astronomical Society
Journal Volume
473
Journal Issue
1
Pages
L36-L40
Date Issued
2018
Author(s)
Abstract
Wave dark matter (ψDM) composed of extremely light bosons (mψ ∼ 10−22 eV), with quantum pressure suppressing structures below a kpc-scale de Broglie wavelength, has become a viable dark matter candidate. Compared to the conventional free-particle ψDM (FPψDM), the extreme-axion ψDM model (EAψDM) proposed by Zhang & Chiueh features a larger cut-off wavenumber and a broad spectral bump in the matter transfer function. Here, we conduct cosmological simulations to compare the halo abundances and assembly histories at z = 4-11 between three different scenarios: FPψDM, EAψDM and cold dark matter (CDM). We show that EAψDM produces significantly more abundant low-mass haloes than FPψDM with the same mψ, and therefore could alleviate the tension in mψ required by the Lyα forest data and by the kpc-scale dwarf galaxy cores. We also find that, compared to the CDM counterparts, massive EAψDM haloes are, on average, 3-4 times more massive at z = 10-11 due to their earlier formation, undergo a slower mass accretion at 7 ≲ z ≲ 11, and then show a rapidly rising major merger rate exceeding CDM by ∼50 per cent at 4 ≲ z ≲ 7. This fact suggests that EAψDM haloes may exhibit more prominent starbursts at z ≲ 7. © 2017 The Authors
Subjects
Dark matter; Galaxies: evolution; Galaxies: high-redshift; Galaxies: luminosity function; Mass function
SDGs
Type
journal article