The scaling relationship between baryonic mass and stellar disc size in morphologically late-type galaxies
Journal
Monthly Notices of the Royal Astronomical Society
Journal Volume
473
Journal Issue
4
Pages
5468-5475
Date Issued
2018
Author(s)
Wu P.-F.
Abstract
Here I report the scaling relationship between the baryonic mass and scale-length of stellar discs for ~1000 morphologically late-type galaxies. The baryonic mass-size relationship is a single power law R* ∝ Mb0.38 across ~3 orders of magnitude in baryonic mass. The scatter in size at fixed baryonic mass is nearly constant and there are no outliers. The baryonic mass- size relationship provides a more fundamental description of the structure of the disc than the stellar mass-size relationship. The slope and the scatter of the stellar mass-size relationship can be understood in the context of the baryonic mass-size relationship. For gas-rich galaxies, the stars are no longer a good tracer for the baryons. High-baryonic-mass, gas-rich galaxies appear to be much larger at fixed stellar mass because most of the baryonic content is gas. The stellar mass-size relationship thus deviates from the power-law baryonic relationship, and the scatter increases at the low-stellar-mass end. These extremely gas-rich low-mass galaxies can be classified as ultra-diffuse galaxies based on the structure. © 2017 The Author.
Subjects
Galaxies: fundamental parameters; Galaxies: spiral; Galaxies: structure
Other Subjects
Stars; Galaxies: fundamental parameters; Galaxies: spirals; Galaxies:structure; Late-type; Mass disk; Mass size; Power-law; Scaling relationships; Stellar disks; Stellar mass; Galaxies
Type
journal article