Einasto profiles and the dark matter power spectrum

Ludlow, Aaron D.; Angulo, Raúl E.

Abstract

We study the mass accretion histories (MAHs) and density profiles of dark matter haloes using N-body simulations of self-similar gravitational clustering from scale-free power spectra, P(k) ∝ kn. We pay particular attention to the density profile curvature, which we characterize using the shape parameter, α, of an Einasto profile. In agreement with previous findings, our results suggest that, despite vast differences in their MAHs, the density profiles of virialized haloes are remarkably alike. Nonetheless, clear departures from self-similarity are evident: For a given spectral index, α increases slightly but systematically with ‘peak height’, ν ≡ δsc/σ(M, z), regardless of mass or redshift. More importantly, however, the ‘α–ν’ relation depends on n: The steeper the initial power spectrum, the more gradual the curvature of both the mean MAHs and mean density profiles. These results are consistent with previous findings connecting the shapes of halo mass profiles and MAHs, and imply that dark matter haloes are not structurally self-similar but, through the merger history, retain a memory of the linear density field from which they form.

Citation

Ludlow, A. D., & Angulo, R. E. (2017). Einasto profiles and the dark matter power spectrum. Monthly Notices of the Royal Astronomical Society: Letters, 465(1), L84-L88. https://doi.org/10.1093/mnrasl/slw216

• Journal Article Type: Article
• Acceptance Date: Oct 17, 2016
• Online Publication Date: Oct 19, 2016
• Publication Date: Oct 19, 2017
• Deposit Date: Jul 5, 2017
• Publicly Available Date: Jul 5, 2017
• Journal: Monthly Notices of the Royal Astronomical Society: Letters
• Electronic ISSN: 1745-3933
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 465
• Issue: 1
• Pages: L84-L88
• DOI: https://doi.org/10.1093/mnrasl/slw216
• Public URL: https://durham-repository.worktribe.com/output/1354266