The role of inner halo angular momentum on bar formation and evolution

Various studies have shown that dark matter halo properties like concentration, triaxiality, spin, etc., play an essential role in the dynamical processes of bar instability. We have investigated the role of inner (within disk region) halo angular momentum distribution on the bar formation and evolution. We have performed a series of high-resolution N-body experiments with Milky Way-type galaxies. These models are initiated with similar disks while increasing the inner halo angular momentum of the surrounding dark matter halo. The bar triggers earlier for the model with a higher inner halo angular momentum than the lower ones, similar to studies claiming the role of halo spins. However, the bar secular evolution shows growth for all the models, irrespective of inner halo angular momentum, contradicting the role of high spin in bar secular dampening claimed in earlier studies. The model with the highest inner angular momentum show pronounced box/peanut/x-shaped bulges compared to the lowest one. Our preliminary results on the role of halo angular momentum discontinuity show that the secular growth of the bar follows in models with continuity of the halo angular momentum. In contrast, the bar dampens in secular evolution for discontinuous angular momentum halo models. These studies provide insight into complex bar formation processes.