When Hot Disks Meet Spinning Halos: How Bars Can Still Form
Kataria’s study shows that even a kinematically hot and thick galactic disk, normally stable against bar formation, can develop a bar if it sits inside a rapidly spinning dark matter halo. Simulations reveal that halo spin greatly enhances angular momentum transfer, by a factor of eight, triggering bar growth that classical stability criteria fail to predict. This mechanism may explain why JWST observes barred galaxies in the early, turbulent universe.
Bars, Spins, and Neighbors: What Shapes the Formation of Galactic Bars?
This study uses MaNGA observations to investigate why some disc galaxies host stellar bars. It shows that bars form mainly due to internal conditions, especially high central stellar mass dominance and low stellar angular momentum. Environmental interactions play a secondary role, sometimes triggering bars in galaxies already close to instability.
Bars Across Time: Tracing Galactic Structures Over 12 Billion Years
Using JWST data, Zoe Le Conte and collaborators traced how stellar bars in disc galaxies evolved over 12 billion years. They found the bar fraction declines from 16% at z ≈ 1–2 to 7% at z ≈ 4, showing that stable discs already existed early in cosmic history. Bar lengths stayed roughly constant, indicating that bars and galaxy discs have grown together over time.