Evolution of galactic discs: multiple patterns, radial migration, and disc outskirts
| Autor: | Ivan Minchev, Peter Erwin, M. Vlajic, Francoise Combes, Alice C. Quillen, P. Di Matteo, Benoit Famaey, Joss Bland-Hawthorn |
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| Přispěvatelé: | Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris) |
| Jazyk: | angličtina |
| Rok vydání: | 2012 |
| Předmět: |
Angular momentum
Cosmology and Nongalactic Astrophysics (astro-ph.CO) Stellar population FOS: Physical sciences Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics 01 natural sciences 0103 physical sciences Surface brightness 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics ComputingMilieux_MISCELLANEOUS Physics [PHYS]Physics [physics] 010308 nuclear & particles physics Velocity dispersion Astronomy and Astrophysics Radius Astrophysics - Astrophysics of Galaxies Accretion (astrophysics) Radial velocity Stars Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) Astrophysics::Earth and Planetary Astrophysics [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] Astrophysics - Cosmology and Nongalactic Astrophysics |
| Zdroj: | Astronomy and Astrophysics-A&A Astronomy and Astrophysics-A&A, 2012, 548, pp.A126. ⟨10.1051/0004-6361/201219198⟩ Astronomy and Astrophysics-A&A, EDP Sciences, 2012, 548, pp.A126. ⟨10.1051/0004-6361/201219198⟩ |
| ISSN: | 0004-6361 |
| DOI: | 10.1051/0004-6361/201219198⟩ |
| Popis: | We investigate the evolution of galactic disks in N-body Tree-SPH simulations. We find that disks, initially truncated at three scale-lengths, can triple their radial extent, solely driven by secular evolution. Both Type I (single exponential) and Type II (down-turning) observed disk surface-brightness profiles can be explained by our findings. We relate these results to the strong angular momentum outward transfer, resulting from torques and radial migration associated with multiple patterns, such as central bars and spiral waves of different multiplicity. We show that even for stars ending up on cold orbits, the changes in angular momentum exhibit complex structure as a function of radius, unlike the expected effect of transient spirals alone. Focussing on one of our models, we find evidence for non-linear coupling among m=1, 2, 3 and 4 density waves, where m is the pattern multiplicity. We suggest that the naturally occurring larger resonance widths at galactic radii beyond four scale-lengths may have profound consequences on the formation and location of breaks in disk density profiles, provided spirals are present at such large distances. We also consider the effect of gas inflow and show that when in-plane smooth gas accretion of ~5 M_sun/yr is included, the outer disks become more unstable, leading to a strong increase in the stellar velocity dispersion. This, in turn, causes the formation of a Type III (up-turning) profile in the old stellar population. We propose that observations of Type III surface brightness profiles, combined with an up-turn in the stellar velocity dispersions beyond the disk break, could be a signature of ongoing gas-accretion. The results of this study suggest that disk outskirts comprised of stars migrated from the inner disk would have relatively large radial velocity dispersions, and significant thickness when seen edge-on. [Abridged] Comment: Replaced with accepted version. New Fig. 5 added, Section 10 decreased in size, old Fig. 17 removed. Conclusions remain the same. High-resolution version can be found at http://www.ivanminchev.com |
| Databáze: | OpenAIRE |
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