Dark Matter Density in Disk Galaxies

TL;DR

This paper discusses the discrepancy between predicted and observed dark matter densities in galaxy centers within LCDM models, exploring potential physical processes to resolve this inconsistency.

Contribution

It reviews proposed mechanisms that could reduce dark matter density in galaxy centers, addressing a key challenge in LCDM cosmology.

Findings

Predicted inner dark matter densities are higher than observational estimates.

Physical processes may reduce dark matter density, aligning models with observations.

Review of mechanisms proposed for density reduction.

Abstract

I show that the predicted densities of the inner dark matter halos in LCDM models of structure formation appear to be higher than estimates from real galaxies and constraints from dynamical friction on bars. This inconsistency would not be a problem for the LCDM model if physical processes that are omitted in the collisionless collapse simulations were able to reduce the dark matter density in the inner halos. I review the mechanisms proposed to achieve the needed density reduction.