Made-To-Measure Models of Self-Similar Triaxial Halos with Steep Inner Density Gradients

TL;DR

This paper introduces a refined Made-to-Measure method to create self-similar, triaxial halo models with steep inner density gradients, demonstrating their stability and analytical representation.

Contribution

It advances the Made-to-Measure technique by incorporating orbital averaging intrinsically and provides analytical density profiles for complex triaxial halos.

Findings

Models retain shape during evolution

Analytical density profiles are efficiently derived

Halo models recover shape after perturbations

Abstract

We use the Made-to-Measure method to construct N-body realizations of self-similar, triaxial ellipsoidal halos having cosmologically realistic density profiles. Our implementation parallels previous work with a few numerical refinements, but we show that orbital averaging is an intrinsic feature of the force of change equation and argue that additional averaging or smoothing schemes are redundant. We present models having the Einasto radial mass profile that range from prolate to strongly triaxial. We use a least-squares polynomial fit to the expansion coefficients to obtain an analytical representation of the particle density from which we derive density contours and eccentricity profiles more efficiently than by the usual particle smoothing techniques. We show that our N-body realizations both retain their shape in unconstrained evolution and recover it after large amplitude perturbations.