Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-60049
Loebman, S R; Roškar, R; Debattista, V P; Ivezić, Ž; Quinn, T R; Wadsley, J (2011). The Genesis of the Milky Way's thick disk via stellar migration. Astrophysical Journal, 737(1):8.
|Accepted Version (English)|
View at publisher
We compare the spatial, kinematic, and metallicity distributions of stars in the Milky Way disk, as observed by the Sloan Digital Sky Survey and Geneva-Copenhagen Survey, to predictions made by N-body simulations that naturally include radial migration as proposed by Sellwood & Binney. In these simulations, stars that migrate radially outward feel a decreased restoring force, consequentially they reach larger heights above the mid-plane. We find that this model is in qualitative agreement with observational data and can explain the disk's double-exponential vertical structure and other characteristics as due to internal evolution. In particular, the model reproduces observations of stars in the transition region between exponential components, which do not show a strong correlation between rotational velocity and metallicity. Although such a correlation is present in young stars because of epicyclic motions, radial migration efficiently mixes older stars and weakens the correlation. Classifying stars as members of the thin or thick disk by either velocity or metallicity leads to an apparent separation in the other property, as observed. We find a much stronger separation when using [α/Fe], which is a good proxy for stellar age. The model success is remarkable because the simulation was not tuned to reproduce the Galaxy, hinting that the thick disk may be a ubiquitous Galactic feature generated by stellar migration. Nonetheless, we cannot exclude the possibility that some fraction of the thick disk is a fossil of a more violent history, nor can radial migration explain thick disks in all galaxies, most strikingly those which counterrotate with respect to the thin disk.
30 downloads since deposited on 23 Feb 2012
7 downloads since 12 months
|Item Type:||Journal Article, refereed, original work|
|Communities & Collections:||07 Faculty of Science > Institute for Computational Science|
|Dewey Decimal Classification:||530 Physics|
|Deposited On:||23 Feb 2012 21:40|
|Last Modified:||15 Feb 2014 05:58|
|Publisher:||Institute of Physics Publishing|
Users (please log in): suggest update or correction for this item
Repository Staff Only: item control page