An Accurate Comprehensive Approach to Substructure: I. Accreted Subhaloes

Abstract

This is the first of a series of three Papers devoted to the study of halo substructure in hierarchical cosmologies by means of the CUSP formalism. In the present Paper we derive the properties of subhaloes and diffuse dark matter (dDM) accreted onto haloes and their progenitors. Specifically, we relate the dDM present at any time in the inter-halo medium of the real Universe or a cosmological simulation with the corresponding free-streaming mass or the halo resolution mass, respectively, and establish the link between subhaloes and their seeds in the initial density field. By monitoring the collapse and virialisation of haloes, we derive from first principles and with no single free parameter the abundance and radial distribution of dDM and subhaloes accreted onto them. Our predictions are in excellent agreement with the results of simulations, but for the predicted fraction of accreted dDM, which is larger than reported in previous works as they only count the dDM accreted onto the final halo, not onto its progenitors. The derivation pursued here clarifies the origin of some key features of substructure. Overall, our results demonstrate that CUSP is a powerful tool for understanding halo substructure and extending the results of simulations to haloes with arbitrary masses, redshifts and formation times in any hierarchical cosmology endowed with random Gaussian density perturbations.

12 pages, 5 figures. Accepted for publication in MNRAS. Minor changes to match with the published version

References in corpus (11)

• Disruption of Dark Matter Substructure: Fact or Fiction?
• Dark Matter Substructure in Numerical Simulations: A Tale of Discreteness Noise, Runaway Instabilities, and Artificial Disruption
• SubHaloes going Notts: The SubHalo-Finder Comparison Project
• The Population of Dark Matter Subhaloes: Mass Functions and Average Mass Loss Rates
• The Unorthodox Orbits of Substructure Halos
• HBT+: an improved code for finding subhalos and building merger trees in cosmological simulations
• The statistics of the subhalo abundance of dark matter haloes
• Nonlinear evolution of dark matter subhalos and applications to warm dark matter
• Subhalo statistics of galactic halos: beyond the resolution limit
• Tidal Mass Loss from Collisionless Systems
• An Accurate Comprehensive Approach to Substructure: II. Stripped Subhaloes

Cited by in corpus (3)

• The Universal Specific Merger Rate of Dark Matter Halos
• An Accurate Comprehensive Approach to Substructure: III. Masses and Formation Times of the Host Haloes
• Accurate Analytic Mass-Scale Relations for Dark Matter Haloes of all Masses and Redshifts