Tidal Tracks and Artificial Disruption of Cold Dark Matter Halos

TL;DR

This paper introduces an improved model for tidal heating of dark matter subhalos that accurately matches simulations and explains artificial disruption effects, impacting subhalo mass function estimates.

Contribution

It presents a second-order extension to tidal heating models and demonstrates its effectiveness in reproducing simulation results and artificial disruption phenomena.

Findings

The revised model accurately matches tidal tracks in N-body simulations.

Artificial disruption causes a 10-20% underestimation of subhalo mass functions.

The model explains finite resolution effects in dark matter simulations.

Abstract

We describe a simple extension to existing models for the tidal heating of dark matter subhalos which takes into account second order terms in the impulse approximation for tidal heating. We show that this revised model can accurately match the tidal tracks along which subhalos evolve as measured in high-resolution N-body simulations. We further demonstrate that, when a constant density core is introduced into a subhalo, this model is able to quantitatively reproduce the evolution and artificial disruption of N-body subhalos arising from finite resolution effects. Combining these results we confirm prior work indicating that artificial disruption in N-body simulations can result in a factor two underestimate of the subhalo mass function in the inner regions of host halos, and a 10--20% reduction over the entire virial volume.