Abstract Details
| Name: Sandeep Kumar Kataria Affiliation: JAP-IIA, Bangalore Conference ID: ASI2017_551 Title : Studying the Formation and Structure of Bars in Dark Matter Dominated Spiral Galaxies with and without bulges. Authors and Co-Authors : Sandeep Kumar Kataria(JAP-IIA, Bangalore), Mousumi Das(IIA, Bangalore) Abstract Type : Oral Abstract Category : Extragalactic astronomy Abstract : We present N body simulations of bar formation in dark matter dominated disk galaxies. Bars are elongated structures found in the centers of spiral galaxies. Nearly two thirds of all observed spiral galaxies in the nearby universe have bars. Bar formation in isolated galaxies occurs due to the exchange of angular momentum between the different mass components (disk, bulge and dark matter halo). Previous studies have shown that the interaction of the dark matter halo with the disk component in spiral galaxies is very important for bar evolution. In this study we investigate the role played by classical bulges in the formation and evolution of bars. We first made various models of disk galaxies using the GalIC code (Yurin et al 2014) that had increasing bulge masses. We started with models with no bulge and increased the bulge mass to form galaxies with bulge dominated disks. We evolved these models with Gadget-2 code (Springel et al 2005) and studied the bar instabilities that formed. We calculated how the bar strength varied with time for the different bulge mass fractions. We find that for small bulges the bar forms faster than that in bulgeless galaxies. But for massive bulges the bar forms more slowly. For very high bulge to disk mass ratio the bars become weaker or does not form at all. We also explore how the bar pattern speed varies with bulge mass. Our results indicate that early type spiral galaxies can still form strong bars in spite of having massive bulges and that bulgeless galaxies will in general have weak bars. |