Analytical halo models of cosmic tidal fields

Abstract

The non-linear cosmic web environment of dark matter haloes plays a major role in shaping their growth and evolution, and potentially also affects the galaxies that reside in them. We develop an analytical (halo model) formalism to describe the tidal field of anisotropic halo-centric density distributions, as characterised by the halo-centric tidal tensor $⟨T_{ij}⟩(<R)$ spherically averaged on scale $R\sim 4R_{\mathrm{vir}}$ for haloes of virial radius $R_{\mathrm{vir}}$. We focus on axisymmetric anisotropies, which allows us to explore simple and intuitive toy models of (sub)halo configurations that exemplify some of the most interesting anisotropies in the cosmic web. We build our models around the spherical Navarro-Frenk-White (NFW) profile after describing it as a Gaussian mixture, which leads to almost fully analytical expressions for the `tidal anisotropy' scalar $\alpha (<4R_{\mathrm{vir}})$ extracted from the tidal tensor. Our axisymmetric examples include (i) a spherical halo at the axis of a cylindrical filament, (ii) an off-centred satellite in a spherical host halo and (iii) an axisymmetric halo. Using these, we demonstrate several interesting results. For example, the tidal tensor at the axis of a pure cylindrical filament gives ${\alpha }^{(\mathrm{fil})}(<R)=1/2$ exactly, for any $R$. Also, $\alpha (<4R_{\mathrm{vir},\mathrm{sat}})$ for a satellite of radius $R_{\mathrm{vir},\mathrm{sat}}$ as a function of its host-centric distance is a sensitive probe of dynamical mass loss of the satellite in its host environment. Finally, we discuss a number of potentially interesting extensions and applications of our formalism that can deepen our understanding of the multi-scale phenomenology of the cosmic web.

18 pages, 8 figures; v2: minor changes, references added. Accepted in MNRAS. Code to implement the models along with example usage can be downloaded from https://bitbucket.org/aparanjape/gaussmixnfw

References in corpus (15)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• The NumPy array: a structure for efficient numerical computation
• Properties of Dark Matter Haloes in Clusters, Filaments, Sheets and Voids
• A universal model for halo concentrations
• The Evolution of Dark Matter Halo Properties in Clusters, Filaments, Sheets and Voids
• Dark Matter Substructure in Numerical Simulations: A Tale of Discreteness Noise, Runaway Instabilities, and Artificial Disruption
• Spin alignment of dark matter haloes in filaments and walls
• The dependence of dark halo clustering on the formation epoch and the concentration parameter
• Environmental dependence in the ellipsoidal collapse model
• Alignments of Voids in the Cosmic Web
• The tidal evolution of dark matter substructure -- I. Subhalo density profiles
• DASH: a library of dynamical subhalo evolution
• Excursion set peaks: the role of shear
• A sea of tides: star formation and the central-satellite dichotomy in a continuum of tidal environments
• On the anisotropic density distribution on large scales

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• Dissecting and Modelling Galaxy Assembly Bias
• The physical origins of low-mass spin bias
• On the kinetic Sunyaev-Zel'dovich effect as an observational probe for halo spin bias
• Separate Universe calibration of the dependence of halo bias on cosmic web anisotropy
• A sea of tides: star formation and the central-satellite dichotomy in a continuum of tidal environments
• The galaxy bias profile of cosmic voids
• Mass accretion rates and multi-scale halo environment in cold and warm dark matter cosmologies
• Superclustering with the Atacama Cosmology Telescope and Dark Energy Survey: II. Anisotropic large-scale coherence in hot gas, galaxies, and dark matter
• Bending the web: exploring the impact of modified gravity on the density field and halo properties within the cosmic web
• The multi-dimensional halo assembly bias can be preserved when enhancing halo properties with HALOSCOPE