On the Scaling Relations of Disk Galaxies

TL;DR

This paper reviews the physical basis of scaling laws in disk galaxies, compares theoretical and observed relations, and discusses challenges in modeling baryonic processes and measurement techniques.

Contribution

It provides a comprehensive review of the scaling relations of disk galaxies and discusses the difficulties in accurately modeling baryonic effects and measurement criteria.

Findings

Tully-Fisher and disk size relations show low scatter

Analytical and observed scaling laws are in good agreement

Modeling baryon fraction and star formation efficiency remains challenging

Abstract

The physical background of scaling laws of disk galaxies is reviewed. The match between analytically derived and observed scaling laws is briefly discussed. Accurate modeling of the fraction of baryons that end populating a disk, and the conversion efficiency of those into stars, remains a challenging task for numerical simulations. The measurement of rotational velocity tends to be made with criteria of convenience rather than through rigorous definition. And yet, the Tully-Fisher and the disk size vs. rotational velocity relations exhibit surprisingly low scatter. Practical recipes (and costs) to optimize the quality of template relations are considered.