Evolution of Galactic Bar Dynamics Revealed in New Research

Recent research published in the paper titled "The redshift evolution of galactic bar pattern speed in TNG50" by Asiyeh Habibi and colleagues investigates the dynamics of galactic bars in simulated galaxies. The study focuses on how the properties of these bars, including their length and pattern speed, evolve over time, particularly as the redshift changes.

Key findings from the research indicate that the median pattern speed of galactic bars increases with higher redshift values, suggesting that bars rotate faster in the earlier universe. Specifically, the mean pattern speed at redshift z=1.0 is approximately 70.98 km/s/kpc, which decreases to about 33.65 km/s/kpc at z=0.0. This implies that bars in the past rotated nearly twice as fast as those observed today.

The study also highlights the relationship between bar length and the corotation radius, noting that while the length of the bars increases over time, the corotation radius grows at a faster rate. This results in a decrease in the overall pattern speed of the bars as the universe evolves. The authors discuss potential mechanisms that could lead to this slowdown, including the impact of galactic mergers, although they conclude that mergers are not the primary factor influencing the mean pattern speed in the studied redshift range.

Additionally, the research finds no correlation between the gas fraction in galaxies and the fast bar tension, indicating that the presence of gas does not mitigate the observed slowdown of galactic bars.

This research contributes to our understanding of galactic evolution and the dynamics of bar structures within galaxies, providing insights into the historical behavior of these features in the cosmos. The findings may have implications for future studies on galaxy formation and evolution, particularly in the context of cosmological simulations.

For further details, the paper can be accessed at arXiv:2409.02456.