Inflow-driven galaxy evolution - II: A hierarchy in the scaling relations of star-forming galaxies
Abstract
The star-forming main sequence (SFMS; M⋆--sSFR), the gas-to-stellar mass relation (M⋆--Mgas/M⋆), and the mass--metallicity relation (MZR; M⋆--Zgas) are three core scaling relations for star-forming galaxies, and together they encode the information about the baryon cycle that operates during galaxy evolution. We investigate how these relations emerge by modelling the gas flows that regulate the baryon cycle, using both an ideal and a cosmological gas flow model, and identify a hierarchy among the three relations, with one further parameter entering the scatter budget at each step. In our model, the SFMS and its scatter are set primarily by the formation time of the host halo, with a weak dependence on the star formation efficiency and the mass-loading factor. The gas-to-stellar mass relation follows from the ratio of the sSFR to the star formation efficiency, and inherits the scatter of both. The MZR in turn follows from the gas-to-stellar mass relation together with the mass-loading factor, their relative contributions depending on the galaxy evolutionary state between the inflow-driven regime and equilibrium. This hierarchy naturally introduces further correlations among the three relations, such as the fundamental plane of star formation (M⋆--Mgas--SFR), the fundamental metallicity relation (M⋆--SFR--Zgas) and its gaseous counterpart (M⋆--Mgas--Zgas), and the correlations of each relation with galaxy size, which traces the star formation efficiency through the star formation law. Together, the three core scaling relations and the higher-dimensional correlations among them follow from a single framework, providing a foundation for linking the observables of star-forming galaxies to the underlying baryon cycle.
Related
- Evidence for Hierarchical Turbulent Scaling in Nearby Star-Forming Galaxies
- Evolution of the morphology-density and morphology-mass relations of quiescent galaxies at 0.5 {2}lt;z<$ 2.5 in the COSMOS-Web survey
- From Scaling Relations to Physical Laws: Constraining the Physics of Star Formation Across Local Galaxies
- Understanding galaxies and the origin of the golden mass through the study of scaling relations across cosmic history
- The Physical Origins of Scatter in the Dust Attenuation Scaling Relation of Star-Forming Galaxies: Star--Dust Geometry
BibTeX
@misc{wang2026inflowdriven,
title = {{Inflow-driven galaxy evolution - II: A hierarchy in the scaling relations of star-forming galaxies}},
author = {Kai Wang and Carlton Baugh and Sownak Bose and Shaun Cole and Carlos S. Frenk and Cedric Lacey and Julio F. Navarro and Kyle A. Oman and Amélie Saintonge and Tom Theuns},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.12394},
eprint = {2610.12394},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.12394},
}
RIS
TY - UNPB
TI - Inflow-driven galaxy evolution - II: A hierarchy in the scaling relations of star-forming galaxies
AU - Kai Wang
AU - Carlton Baugh
AU - Sownak Bose
AU - Shaun Cole
AU - Carlos S. Frenk
AU - Cedric Lacey
AU - Julio F. Navarro
AU - Kyle A. Oman
AU - Amélie Saintonge
AU - Tom Theuns
PY - 2026
DA - 2026/10/08
PB - arXiv
DO - 10.48550/arxiv.2610.12394
UR - https://arxiv.org/abs/2610.12394
AB - The star-forming main sequence (SFMS; M_⋆--sSFR), the gas-to-stellar mass relation (M_⋆--M_gas/M_⋆), and the mass--metallicity relation (MZR; M_⋆--Z_gas) are three core scaling relations for star-forming galaxies, and together they encode the information about the baryon cycle that operates during galaxy evolution. We investigate how these relations emerge by modelling the gas flows that regulate the baryon cycle, using both an ideal and a cosmological gas flow model, and identify a hierarchy among the three relations, with one further parameter entering the scatter budget at each step. In our model, the SFMS and its scatter are set primarily by the formation time of the host halo, with a weak dependence on the star formation efficiency and the mass-loading factor. The gas-to-stellar mass relation follows from the ratio of the sSFR to the star formation efficiency, and inherits the scatter of both. The MZR in turn follows from the gas-to-stellar mass relation together with the mass-loading factor, their relative contributions depending on the galaxy evolutionary state between the inflow-driven regime and equilibrium. This hierarchy naturally introduces further correlations among the three relations, such as the fundamental plane of star formation (M_⋆--M_gas--SFR), the fundamental metallicity relation (M_⋆--SFR--Z_gas) and its gaseous counterpart (M_⋆--M_gas--Z_gas), and the correlations of each relation with galaxy size, which traces the star formation efficiency through the star formation law. Together, the three core scaling relations and the higher-dimensional correlations among them follow from a single framework, providing a foundation for linking the observables of star-forming galaxies to the underlying baryon cycle.
ER -