A test of invariance of halo surface density for FIRE-2 simulations with cold dark matter and self-interacting dark matter

TL;DR

This study tests the invariance of dark matter halo surface density across galaxy types using FIRE-2 simulations with CDM and SIDM, finding it remains nearly constant and consistent with observations.

Contribution

It demonstrates the invariance of halo surface density in both CDM and SIDM models across a specific galaxy mass range, aligning with observational data.

Findings

Surface density is nearly constant for CDM and SIDM in dwarf galaxies.

Halo surface density from Burkert profile fits matches galactic observations.

Empirical relations between surface density and velocity agree with observed dwarf galaxies.

Abstract

Numerous observations have shown that the dark matter halo surface density, defined as the product of core radius and halo central density of cored dark matter haloes is nearly constant and independent of galaxy mass over a whole slew of galaxy types. Here we calculate the surface density in cold dark matter(CDM) and self-interacting dark matter (SIDM) models including baryons, as well as SIDM without baryons, for dwarf galaxies of masses $\approx 10^{10} M_{\odot}$ using mock catalogs obtained from simulations as part of the Feedback In Realistic Environments project. We find that the dark matter surface density and column density are nearly constant for CDM and SIDM for this mass range. The halo surface density obtained from the Burkert profile fit is consistent with galactic-scale observations within $1\sigma$. We also computed the empirical scaling relations between the central surface density and maximum velocity using the best-fit dark matter profiles, and found that they agree with observations of Milky Way and M31 dwarfs.