Recovering cores and cusps in dark matter haloes using mock velocity field observations

TL;DR

This study uses mock velocity observations to assess how well dark matter halo profiles, whether cuspy or cored, can be distinguished in galaxy rotation data, confirming the reality of observed cores.

Contribution

It demonstrates that high-resolution velocity fields reliably differentiate between cuspy and cored dark matter haloes, validating the observed cores as genuine features.

Findings

Velocity field appearance varies with halo type

Dark matter halo parameters can be accurately recovered

Observed cores are genuine, not artifacts

Abstract

We present mock DensePak Integral Field Unit (IFU) velocity fields, rotation curves, and halo fits for disc galaxies formed in spherical and triaxial cuspy dark matter haloes, and spherical cored dark matter haloes. The simulated galaxies are "observed" under a variety of realistic conditions to determine how well the underlying dark matter halo can be recovered and to test the hypothesis that cuspy haloes can be mistaken for cored haloes. We find that the appearance of the velocity field is distinctly different depending on the underlying halo type. We also find that we can successfully recover the parameters of the underlying dark matter halo. Cuspy haloes appear cuspy in the data and cored haloes appear cored. Our results suggest that the cores observed using high-resolution velocity fields in real dark matter-dominated galaxies are genuine and cannot be ascribed to systematic errors, halo triaxiality, or non-circular motions.