A Critical Assessment of Solutions to the Galaxy Diversity Problem

Abstract

Galactic rotation curves exhibit a diverse range of inner slopes. Observational data indicates that explaining this diversity may require a mechanism that correlates a galaxy's surface brightness with the central-most region of its dark matter halo. In this work, we compare several concrete models that capture the relevant physics required to explain the galaxy diversity problem. We focus specifically on a Self-Interacting Dark Matter (SIDM) model with an isothermal core and two Cold Dark Matter (CDM) models with/without baryonic feedback. In contrast to the CDM case, the SIDM model can lead to the formation of an isothermal core in the halo, and is also mostly insensitive to baryonic feedback processes, which act on longer time-scales. Using rotation curves from 90 galaxies in the Spitzer Photometry and Accurate Rotation Curves (SPARC) catalog, we perform a comprehensive model comparison that addresses issues of statistical methodology from prior works. The best-fit halo models that we recover are consistent with standard CDM concentration-mass and abundance matching relations. We find that both the SIDM and feedback-affected CDM models are better than a CDM model with no feedback in explaining the rotation curves of low and high surface brightness galaxies in the sample. However, when compared to each other, there is no strong statistical preference for either the SIDM or the feedback-affected CDM halo model as the source of galaxy diversity in the SPARC catalog.

JCAP accepted version

References in corpus (12)

• The NumPy array: a structure for efficient numerical computation
• SPARC: Mass Models for 175 Disk Galaxies with Spitzer Photometry and Accurate Rotation Curves
• A mass-dependent density profile for dark matter haloes including the influence of galaxy formation
• Dwarf galaxies in CDM and SIDM with baryons: observational probes of the nature of dark matter
• Dark Matter Heating and Early Core Formation in Dwarf Galaxies
• SIDM on FIRE: Hydrodynamical Self-Interacting Dark Matter simulations of low-mass dwarf galaxies
• NIHAO XIV: Reproducing the observed diversity of dwarf galaxy rotation curve shapes in LCDM
• The central densities of Milky Way-mass galaxies in cold and self-interacting dark matter models
• NIHAO -- XXV. Convergence in the cusp-core transformation of cold dark matter haloes at high star formation thresholds
• NIHAO-XXIII: Dark Matter density shaped by Black Hole feedback
• Degeneracies Between Self-interacting Dark Matter and Supernova Feedback as cusp-core transformation mechanisms
• Testing baryon-induced core formation in $\Lambda$CDM: A comparison of the DC14 and coreNFW dark matter halo models on galaxy rotation curves

Cited by in corpus (6)

• Strong Dark Matter Self-interactions Diversify Halo Populations within and surrounding the Milky Way
• Constraining resonant dark matter self-interactions with strong gravitational lenses
• A semi-analytic study of self-interacting dark-matter haloes with baryons
• Fitting a Self-Interacting Dark Matter Model to Data Ranging From Satellite Galaxies to Galaxy Clusters
• The information on halo properties contained in spectroscopic observations of late-type galaxies
• Cosmological simulations with rare and frequent dark matter self-interactions