Induced Nested Galactic Bars inside Assembling Dark Matter Halos
| Autor: | Clayton Heller, Isaac Shlosman, Lia Athanassoula |
|---|---|
| Přispěvatelé: | Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Beaussier, Catherine |
| Rok vydání: | 2007 |
| Předmět: |
Physics
Star formation Astrophysics (astro-ph) Dark matter FOS: Physical sciences Perturbation (astronomy) Astronomy and Astrophysics Quasar Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics Galaxy [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO] Supernova [PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO] Space and Planetary Science Astrophysics::Earth and Planetary Astrophysics Halo Stellar evolution Astrophysics::Galaxy Astrophysics |
| Zdroj: | The Astrophysical Journal. 657:L65-L68 |
| ISSN: | 1538-4357 0004-637X |
| Popis: | We investigate the formation and evolution of nested bar systems in disk galaxies in a cosmological setting by following the development of an isolated dark matter (DM) and baryon density perturbation. The disks form within the assembling triaxial DM halos and the feedback from the stellar evolution is accounted for in terms of supernovae and OB stellar winds. Focusing on a representative model, we show the formation of an oval disk and of a first generation of nested bars with characteristic sub-kpc and a few kpc sizes. The system evolves through successive dynamical couplings and decouplings, forcing the gas inwards and settles in a state of resonant coupling. The inflow rate can support a broad range of activity within the central kpc, from quasar- to Seyfert-types, supplemented by a vigorous star formation as a by-product. The initial bar formation is triggered in response to the tidal torques from the triaxial DM halo, which acts as a finite perturbation. This first generation of bars does not survive for more than 4--5 Gyr: by that time the secondary bar has totally dissolved, while the primary one has very substantially weakened, reduced to a fat oval. This evolution is largely due to chaos introduced by the interaction of the multiple non-axisymmetric components. Comment: 4 pages, 4 figures, 1 mpeg animation. To be published by the Astrophysical Journal Letters. The animation can be found at http://www.pa.uky.edu/~shlosman/research/galdyn/movies.html Replaced with an updated version (small text corrections) |
| Databáze: | OpenAIRE |
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