The mass distribution in Spiral galaxies

TL;DR

This paper reviews the structural properties of dark and luminous mass distributions in spiral galaxies, highlighting the universal rotation curve and dark halo core properties, and discusses implications for cosmological models.

Contribution

It synthesizes recent observational findings on spiral galaxy mass distributions and discusses their implications for ΛCDM cosmology.

Findings

Rotation curves follow a universal function up to the virial radius

Dark halos have a density core with size correlating to central density

Dark matter's importance decreases with galaxy mass

Abstract

In the past years a wealth of observations has allowed us to unravel the structural properties of the Dark and Luminous mass distribution in spirals. As result, it has been found that their rotation curves follow, out their virial radius, an Universal function (URC) made by two terms: one due to the gravitational potential of a Freeman stellar disk and the other due to that of a dark halo. The importance of the latter is found to decrease with galaxy mass. Individual objects reveal in detail that dark halos have a density core, whose size correlates with its central value. These properties will guide $\Lambda$CDM Cosmology to evolve to match the challenge that observations presently pose.