期刊
ASTRONOMY & ASTROPHYSICS
卷 578, 期 -, 页码 -出版社
EDP SCIENCES S A
DOI: 10.1051/0004-6361/201424281
关键词
Galaxy: disk; Galaxy: evolution; Galaxy: formation; Galaxy: structure; solar neighborhood
资金
- French Agence Nationale de la Recherche (ANR) [ANR-10-BLAN-0508]
- NASA through Hubble Space Telescope Archival Research grant from Space Telescope Science Institute [HST-AR-12837.01-A]
- NASA [NAS5-26555]
- Agence Nationale de la Recherche (ANR) [ANR-10-BLAN-0508] Funding Source: Agence Nationale de la Recherche (ANR)
We develop a chemical evolution model to study the star formation history of the Milky Way. Our model assumes that the Milky Way has formed from a closed-box-like system in the inner regions, while the outer parts of the disc have experienced some accretion. Unlike the usual procedure, we do not fix the star formation prescription (e.g. Kennicutt law) to reproduce the chemical abundance trends. Instead, we fit the abundance trends with age to recover the star formation history of the Galaxy. Our method enables us to recover the star formation history of the Milky Way in the first Gyrs with unprecedented accuracy in the inner (R < 7-8 kpc) and outer (R > 9-10 kpc) discs, as sampled in the solar vicinity. We show that half the stellar mass formed during the thick-disc phase in the inner galaxy during the first 4-5 Gyr. This phase was followed by a significant dip in star formation activity (at 8-9 Gyr) and a period of roughly constant lower-level star formation for the remaining 8 Gyr. The thick-disc phase has produced as many metals in 4 Gyr as the thin-disc phase in the remaining 8 Gyr. Our results suggest that a closed-box model is able to fit all the available constraints in the inner disc. A closed-box system is qualitatively equivalent to a regime where the accretion rate maintains a high gas fraction in the inner disc at high redshift. In these conditions the SFR is mainly governed by the high turbulence of the interstellar medium. By z similar to 1 it is possible that most of the accretion takes place in the outer disc, while the star formation activity in the inner disc is mostly sustained by the gas that is not consumed during the thick-disc phase and the continuous ejecta from earlier generations of stars. The outer disc follows a star formation history very similar to that of the inner disc, although initiated at z similar to 2, about 2 Gyr before the onset of the thin-disc formation in the inner disc.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据