Do Baryons Alter the Halos of Low Surface Brightness Galaxies?

TL;DR

This paper investigates whether baryonic processes can transform the dark matter halos of low surface brightness galaxies from triaxial cusps to round cores, finding that current observations challenge the effectiveness of such baryonic modifications.

Contribution

The study evaluates the impact of baryonic feedback on dark matter halo shapes and densities in LSB galaxies, contrasting observational data with recent galaxy formation simulations.

Findings

Baryonic feedback struggles to sphericalize halos in LSB galaxies.

Observational data suggest halos remain triaxial and dense despite baryonic processes.

Simulations may overestimate baryonic effects on halo structure.

Abstract

High-quality observations of dark matter-dominated low surface brightness (LSB) galaxies indicate that, in contrast to the triaxial, centrally-concentrated cuspy halos formed in collisionless simulations of halo assembly, these galaxies reside in round, roughly constant density cored halos. In order to reconcile these data with galaxy formation in the context of LCDM, processes that alter the shape and density structure of the inner halo are required. We compile observational properties of LSB galaxies to evaluate the plausibility that a previously higher baryonic mass content and feedback from star formation can modify the dark matter halos of these galaxies. We also compare the properties of bulgeless disk galaxies formed in recent simulations to the LSB galaxy sample. We find that observational constraints on LSB galaxy star formation histories, structure, and kinematics make it difficult for baryonic physics to sphericalize and decrease the central density of the dark matter halos of LSB galaxies.