Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics
Scientific paper
2012-03-23
Astronomy and Astrophysics
Astrophysics
Cosmology and Extragalactic Astrophysics
13 pages, 17 figures, submitted. Movies can be found at http://www.ccs.tsukuba.ac.jp/Astro/Members/takashi/research/movies.htm
Scientific paper
More than half of nearby disc galaxies have pseudobulges instead of classical bulges that are though to be end-products of galaxy mergers. Pseudobulges are presumed to develop overtime as a result of secular evolution of galaxy discs. We report simulations of galaxy formation, in which two disc galaxies with disky pseudobulges have formed. Based on the profile decomposition, the bulge-to-total mass ratio of the simulated galaxies is 0.6 for one galaxy and 0.3 for the other. We find that the main formation mechanism of the pseudobulges in our simulations is not the secular evolution of discs but high-redshift starbursts. The progenitors of the pseudobulges form as high-redshift discs with small scale lengths by rapid supply of low angular momentum gas. The orientation of the high-redshift progenitors rapidly changes by the change of the direction of the angular momentum of newly-accreted gas, which blurs the disc properties of the high-redshift discs. Energetic winds following the starbursts remove low angular momentum gas and quench the bulge formation. Once the host haloes are well established, the direction of the angular momentum of newly-accreted gas is better aligned, and high angular momentum gas forms discs with large scale lengths. By redshift 2, before the main disc formation, pseudobulge formation has largely completed in terms of mass. The secular evolution such as bar instability accounts for about 30% of the bulge mass for one galaxy and only 13% for the other but does affect the final shape and kinematic properties of the pseudobulges.
No associations
LandOfFree
The origin of pseudobulges in cosmological simulations of galaxy formation does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The origin of pseudobulges in cosmological simulations of galaxy formation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The origin of pseudobulges in cosmological simulations of galaxy formation will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-38873