The Influence of Subhaloes on Host Halo Properties

Abstract

Within the $\Lambda$CDM cosmology, dark matter haloes are comprised of both a smooth component and a population of smaller, gravitationally bound subhaloes. These components are often treated as a single halo when halo properties, such as density profiles, are extracted from simulations. Recent work has shown that density profiles change substantially when subhalo mass is excluded. In this paper, we expand on this result by analysing the change in three specific host halo properties -- concentration ($c_{\mathrm{NFW}}$), spin (${\lambda }_{\mathrm{Bullock}}$), and shape ($c/a$), -- when calculated only from the smooth component of the halo. This analysis is performed on both Milky Way-mass haloes and cluster-mass haloes in high-resolution, zoom-in, $N$-body simulations. We find that when subhaloes are excluded the median value of (1) $c_{\mathrm{NFW}}$ is enhanced by $\approx 38\pm 12\%$ and $\approx 88\pm 7.7\%$ for Milky Way mass ($10^{12.1}{\text{M}}_{\odot }$) and cluster mass ($10^{14.8}{\text{M}}_{\odot }$) haloes respectively, (2) ${\lambda }_{\mathrm{Bullock}}$ is reduced for Milky Way mass by $\approx 16\pm 6.8\%$ and cluster mass haloes by $\approx 32\pm 8.9\%$. Additionally, with the removal of subhaloes, cluster mass haloes tend to become more spherical as the ratio of minor-to-major axis, $c/a$, increases by $\approx 12\pm 4\%$, whereas Milky Way mass haloes remain approximately the same shape with $c/a$ changed by $\approx 1.2\pm 5.6\%$. The fractional change of each of these properties depends primarily on the amount of mass that is removed from the halo system and, to a lesser extent, mass accretion history. Our findings demonstrate that the properties of the smooth components of dark matter haloes are biased relative to the total mass of the halo including subhaloes.

Accepted to MNRAS 09/26/2023

References in corpus (24)

• The NumPy array: a structure for efficient numerical computation
• The Intrinsic Alignment of Galaxies and its Impact on Weak Gravitational Lensing in an Era of Precision Cosmology
• SubHaloes going Notts: The SubHalo-Finder Comparison Project
• The Shape of the Gravitational Potential in Cold Dark Matter Halos
• The shapes, orientation, and alignment of Galactic dark matter subhalos
• Three Different Types of Galaxy Alignment within Dark Matter Halos
• The alignment of satellite galaxies and cosmic filaments: observations and simulations
• The specific angular momentum of disc galaxies and its connection with galaxy morphology, bar structure and disc gravitational instability
• The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Luminosity and Color Dependence and Redshift Evolution
• The tidal evolution of dark matter substructure -- II. The impact of artificial disruption on subhalo mass functions and radial profiles
• The build up of the correlation between halo spin and the large scale structure
• The Anisotropic Distribution of Satellite Galaxies
• How galaxies lose their angular momentum
• Rhapsody. I. Structural Properties and Formation History From a Statistical Sample of Re-simulated Cluster-size Halos
• SURFS: Riding the waves with Synthetic UniveRses For Surveys
• Symphony: Cosmological Zoom-in Simulation Suites over Four Decades of Host Halo Mass
• A semi-analytic study of self-interacting dark-matter haloes with baryons
• Modeling the gravitational potential of a cosmological dark matter halo with stellar streams
• Illuminating Dark Matter Halo Density Profiles Without Subhaloes
• Connecting Galaxies with Halos Across Cosmic Time: Stellar mass assembly distribution modeling of galaxy statistics
• Notes on the Missing Satellites Problem
• Effects of galaxy intrinsic alignment on weak lensing peak statistics
• Statistics of Dark Matter Substructure: I. Model and Universal Fitting Functions
• Galaxy Galaxy Lensing as a Probe of Galaxy Dark Matter Halos

Cited by in corpus (1)

• Subhalos are Anisotropically Distributed and Aligned with the Smooth Matter Distribution of Their Host Halos