The Super-NFW model: an analytic dynamical model for cold dark matter haloes and elliptical galaxies

TL;DR

This paper introduces the Super-NFW model, an analytic galaxy density profile that closely matches cosmological simulation results and can be extended to more complex geometries, providing a useful tool for studying dark matter haloes and elliptical galaxies.

Contribution

The paper presents the Super-NFW model, an analytic density profile with realistic asymptotic behavior and compatible with basis function expansions for complex galaxy shapes.

Findings

Density profile matches recent simulation evidence

Analytic distribution functions for various anisotropies derived

Model can be extended to axisymmetric and triaxial geometries

Abstract

An analytic galaxy model with $\rho \sim r^{-1}$ at small radii and $\rho \sim r^{-3.5}$ at large radii is presented. The asymptotic density fall-off is slower than the Hernquist model, but faster than the Navarro-Frenk-White (NFW) profile for dark matter haloes, and so in accord with recent evidence from cosmological simulations. The model provides the zeroth-order term in a biorthornomal basis function expansion, meaning that axisymmetric, triaxial and lopsided distortions can easily be added (much like the Hernquist model itself which is the zeroth-order term of the Hernquist-Ostriker expansion). The properties of the spherical model, including analytic distribution functions which are either isotropic, radially anisotropic or tangentially anisotropic, are discussed in some detail. The analogue of the mass-concentration relation for cosmological haloes is provided.