The (Anti-)Hierarchical Evolution of Disk Galaxies

TL;DR

This study uses spectroscopy and imaging to analyze over 200 spiral galaxies across redshifts 0.1 to 1.0, revealing that while total mass growth aligns with hierarchical models, stellar populations evolve anti-hierarchically, especially in low-mass galaxies.

Contribution

It provides observational evidence of anti-hierarchical stellar population evolution within the hierarchical framework of galaxy formation.

Findings

Stellar to total mass ratio remains roughly constant over time.

Low-mass spirals show stronger evolution in mass-to-light ratios than high-mass spirals.

Supports the 'down-sizing' scenario in galaxy evolution.

Abstract

Utilizing spatially resolved VLT/FORS spectroscopy and HST/ACS imaging, we constructed a sample of over 200 field spiral galaxies at redshifts 0.1<z<1.0. We find that the ratio between stellar and total mass remains roughly constant over the observed epochs, in compliance with the framework of hierarchical structure growth. However, the stellar mass-to-light ratios evolve more strongly in low-mass spirals than in high--mass spirals, indicating an anti-hierarchical evolution of their stellar populations (aka "down-sizing").