Evolution of bar formation in galaxies over the last 6 giga-years

TL;DR

This study investigates how the formation of bars in disk galaxies has evolved over the last 6 billion years, revealing that disk stability influences bar presence and that bar fractions are lower in earlier cosmic epochs.

Contribution

It provides a comparative analysis of bar fractions in local and distant galaxies, emphasizing the role of disk stability and structural parameters in bar formation over cosmic time.

Findings

Bar fraction increases with stellar mass in local galaxies.

Distant galaxies show a lower bar fraction, indicating less stable disks in earlier epochs.

Bars are more common in disk-dominated galaxies at all redshifts.

Abstract

This work examines the evolution of bar formation in disk galaxies over the last 6 giga-years by analyzing the barred galaxy fraction as a function of key structural parameters. A representative sample of local and distant field galaxies was studied using bar detection techniques based on elliptical isophotes and Fourier decomposition. The analysis focuses on the dependence of bar formation on stellar mass, color index, and bulge-to-total ratio (B/T). In the local universe, the bar fraction increases with stellar mass and is higher in red, more evolved galaxies, suggesting that disk stability plays a fundamental role in bar formation. In contrast, distant galaxies exhibit a significantly lower bar fraction, indicating that dynamically unstable disks in earlier cosmic epochs limited both the formation and persistence of bars. Bars are more frequent in galaxies with disk-dominated structures (low B/T) at all redshifts; however, even these systems show a reduced bar fraction at higher redshift. Overall, the results highlight the importance of disk stabilization in driving the morphological evolution of galaxies across cosmic time.