Kawata, D;
Brook, CB;
Rahimi, A;
Gibson, BK;
(2016)
Geometrical Structures of Chemically Decomposed Thick and Thin Disk Populations.
In: Skillen, Ian and Balcells, Marc and Trager, Scott C., (eds.)
Proceedings of Astronomical Society of the Pacific Conference Series - Multi-object Spectroscopy in the Next Decade: Big Questions, Large Surveys, and Wide Fields.
Astronomical Society of the Pacific: Canary Islands, Spain.
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Abstract
We summarize the thick and thin disk formation commonly seen in cosmological N-body simulations. As suggested in Brook et al. (2004), a hierarchical clustering scenario causes multiple minor gas-rich mergers, and leads to the formation of a kinematically hot disk, thick disk population, at a high redshift. Once the mergers become less significant at a later epoch, the thin disk population starts building up. Because in this scenario the thick disk population forms intensively at high redshift through multiple gas-rich mergers, the thick disk population is compact and has systematically higher [α/Fe] abundance than the thin disk population. We discuss that the thick disk population would be affected by the formation of the thin disk and suffer from the radial migration, which helps the thick disk population to be observed in the solar neighborhood. In addition, we show that the current cosmological simulations also naturally predict that the thin disk population is flaring at the outer region. As shown in Rahimi et al. (2014), at high vertical height from the disk plane, the compact thick disk population (low metallicity and high [α/Fe]) is dominant in the inner region and the flaring thin disk population (high metallicity and low [α/Fe]) contributes more in the outer region. This helps to explain the positive radial metallicity gradient and negative radial [α/Fe] gradient observed at high vertical height in the Milky Way stellar disk.
| Type: | Proceedings paper |
|---|---|
| Title: | Geometrical Structures of Chemically Decomposed Thick and Thin Disk Populations |
| Event: | Astronomical Society of the Pacific Conference Series - Multi-object Spectroscopy in the Next Decade: Big Questions, Large Surveys, and Wide Fields |
| Location: | Teatro Circo de Marte, Santa Cruz de La Palma, Canary Islands, Spain |
| Open access status: | An open access version is available from UCL Discovery |
| Publisher version: | http://www.aspbooks.org/a/volumes/article_details/... |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/1569375 |
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