Formation time-scales for stellar bars in diverse galactic discs

Area of Science:

• Astrophysics
• Galactic Dynamics
• Computational Astrophysics

Background:

• Stellar bars are common features in disc galaxies.
• Understanding bar formation is crucial for galactic evolution models.
• Previous studies focused on simpler disc and halo conditions.

Purpose of the Study:

• Investigate stellar bar formation in diverse disc galaxy simulations.
• Quantify the impact of disc thickness, turbulence, and dark matter halo properties on bar growth.
• Extend bar formation criteria to high-redshift galaxy analogues.

Main Methods:

• Conducted 145 numerical simulations of disc galaxies.
• Included live and static dark matter haloes.
• Analyzed bar growth time-scales and disc stability criteria (e.g., Efstathiou-Lake-Negroponte parameter, Ostriker-Peebles ratio).

Main Results:

• Bar formation time-scale correlates with disc stability criteria in a power law.
• Specific stability thresholds ([Formula: see text], [Formula: see text], [Formula: see text]) predict bar formation within a Hubble time for Milky Way-like discs in live haloes.
• Higher velocity dispersion delays bar growth; an empirical relation is derived for live halo models.

Conclusions:

• Disc structure and kinematics significantly regulate secular bar formation.
• Bars form slower and require greater instability in static dark matter haloes compared to live ones.
• The findings provide refined criteria for predicting bar formation in cosmological simulations.