Made-to-Measure Dark Matter Haloes, Elliptical Galaxies and Dwarf Galaxies in Action Coordinates

Abstract

We provide a family of action-based distribution functions (DFs) for the double-power law family of densities often used to model galaxies. The DF itself is a double-power law in combinations of the actions, and reduces to the known limits in the case of a pure power-law at small and large radii. Our method enables the velocity anisotropy of the model to be tuned, and so the anisotropy in the inner and outer parts can be specified for the application in hand. We provide self-consistent DFs for the Hernquist and Jaffe models - both with everywhere isotropic velocity dispersions, and with kinematics that gradually becomes more radially anisotropic on moving outwards. We also carry out this exercise for a cored dark-matter model. These are tailored to represent dark haloes and elliptical galaxies respectively with kinematic properties inferred from simulations or observational data. Finally, we relax a cored luminous component within a dark matter halo to provide a self-consistent model of a dwarf spheroidal embedded in dark matter. The DFs provide us with non-rotating spherical stellar systems, but one of the virtues of working with actions is the relative ease with which such models can be converted into axisymmetry and triaxiality.

12 pages, MNRAS, in press (only minor modifications from the first version)

References in corpus (7)

• The SAURON project -- X. The orbital anisotropy of elliptical and lenticular galaxies: revisiting the (V/sigma,epsilon) diagram with integral-field stellar kinematics
• A universal density slope - velocity anisotropy relation for relaxed structures
• Constraining the Galaxy's dark halo with RAVE stars
• Dark matter content and internal dynamics of NGC 4697: NMAGIC particle models from slit data and planetary nebulae velocities
• Physical properties underlying observed kinematics of satellite galaxies
• Hamiltonians of Spherically Symmetric, Scale-Free Galaxies in Action-Angle Coordinates
• A Very Simple Cusped Halo Model

Cited by in corpus (12)

• The first all-sky view of the Milky Way stellar halo with Gaia+2MASS RR Lyrae
• Dynamical evidence for a morphology-dependent relation between the stellar and halo masses of galaxies
• Stellar halo substructure generated by bar resonances
• The Kinematic Properties of Milky Way Stellar Halo Populations
• Predicting the dark matter velocity distribution in galactic structures: tests against hydrodynamic cosmological simulations
• Action-based models for dwarf spheroidal galaxies and globular clusters
• A Versatile and Accurate Method for Halo Mass Determination from Phase-Space Distribution of Satellite Galaxies
• Towards a more rigorous treatment of uncertainties on the velocity distribution of dark matter particles for capture in stars
• Near-Gaussian distributions for modelling discrete stellar velocity data with heteroskedastic uncertainties
• The Doubloon Models of Dark Haloes
• Made-to-Measure Modelling of Globular Clusters
• Scaling Relations in the Phase-Space Structure of Dark Matter Haloes