| Abstract : | In this study, we run N-body simulations of Milky Way-type disk galaxies to study the evolution of Box/Peanut/X-shaped (BPX) bulges resulting from the secular evolution of the disk galaxies. Understanding the secular evolution processes in the disk galaxy systems provides an insight into galaxy formation and evolution. In these N-body experiments, we prepare models of disk galaxies that differ in the inner angular momentum of halos. The inner angular momentum is measured in terms of the spin parameter. Spin parameter varies from 0 to 0.1 in our models, as seen in most state-of-the-art cosmological simulations ( Eagle, Illustris, IllustrisTNG, etc.). We evolve these self-gravitating systems in isolation which develops a bar in the stellar disk within a couple of Gyrs. We confirm that bar triggers earlier with higher spinning dark matter halo, resulting from the faster exchange of angular momentum from disk to halo component with the increasing spin of halos. In the secular evolution phase, the bar buckles and leads to vertical thickening, resulting in BPX bulges. Our results show that the BPX bulges are more pronounced in high spinning halos which provide observational constraints for the spin of surrounding dark matter halos. Further, our results bring out the multiple buckling of the bar in high spinning halos cases. The time period of the second buckling (1 Gyr) is much larger than that of the first buckling (~150 Myr). |
