Effects of the Central Mass Concentration on Bar Formation in Disk Galaxies by Dajeong Jang et al. on Wednesday 30 November

While bars are common in disk galaxies, their formation conditions are not

well understood. We use $N$-body simulations to study bar formation and

evolution in isolated galaxies consisting of a stellar disk, a classical bulge,

and a dark halo. We consider 24 galaxy models that are similar to the Milky Way

but differ in the mass and compactness of the classical bulge and halo

concentration. We find that the bar formation requires

$(Q_{T,\text{min}}/1.2)^2 + (\text{CMC}/0.05)^2\lesssim 1$, where

$Q_{T,\text{min}}$ and CMC refers to the minimum value of the Toomre stability

parameter and the central mass concentration, respectively. Bars tend to be

stronger, longer, and rotate slower in galaxies with a less massive and less

compact bulge and halo. All bars formed in our models correspond to slow bars.

A model with the bulge mass of $\sim10$--$20$\% of the disk under a

concentrated halo produces a bar similar to the Milky-Way bar. We discuss our

findings in relation to other bar formation criteria suggested by previous

studies.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.16816v1