The Link between the Baryonic Mass Distribution and the Rotation Curve Shape

TL;DR

This paper demonstrates that galaxy rotation curves can be effectively modeled by scaling the baryonic mass contributions, indicating a close link between baryonic matter distribution and total mass, including dark matter.

Contribution

It introduces a baryonic scaling model that fits a wide range of galaxy rotation curves with only two free parameters, highlighting a local coupling between baryonic mass and total mass.

Findings

Baryonic scaling can explain most galaxy rotation curves.

HI scaling fails in some early-type spirals, possibly due to observational issues.

The model supports a link between baryonic mass distribution and dark matter presence.

Abstract

The observed rotation curves of disc galaxies, ranging from late-type dwarf galaxies to early-type spirals, can be fit remarkably well simply by scaling up the contributions of the stellar and HI discs. This `baryonic scaling model' can explain the full breadth of observed rotation curves with only two free parameters. For a small fraction of galaxies, in particular early-type spiral galaxies, HI scaling appears to fail in the outer parts, possibly due to observational effects or ionization of the HI. The overall success of the baryonic scaling model suggests that the well-known global coupling between the baryonic mass of a galaxy and its rotation velocity (known as the baryonic Tully-Fisher relation), applies at a more local level as well, and it seems to imply a link between the baryonic mass distribution and the distribution of total mass (including dark matter).