“Research Interests”的版本间差异
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Our research aims are to study the formation, evolution, and structure of galaxies. A central theme of the group’s research for many years has been stellar clusters and the structure of the Milky Way. |
Our research aims are to study the formation, evolution, and structure of galaxies. A central theme of the group’s research for many years has been stellar clusters and the structure of the Milky Way. |
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==Stars and the Galactic structure== |
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Galaxies are fundamental units of matter in the Universe, and understanding their formation and evolution is a problem of central importance. There are a number of complementary routes to gaining such understanding. One method seeks to unravel the history of our own and nearby galaxies through the detailed study of their component stars and star clusters. Both theoretical modeling and observational work on the Milky Way are carried out in the group. For example, present research topics include the kinematical and dynamical properties of stellar clusters, abundance gradients and their evolution along the Milky Way disk, the G-dwarf problem, and Galactic chemical evolution. |
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Characterising and classifying the stars around us is crucial if we are to use them to study the structure of our galaxy. Spectroscopic surveys such as LAMOST are providing spectra for millions of stars, but only by determining properties such as stellar types (and hence distances) and ages will we be fully able to exploit these datasets. Meanwhile, we are able to discover a large sample of Hyper-velocity stars, which will provide unique constraints on the shape of the potential of the Galaxy’s dark matter halo. |
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LAMOST..... |
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== Open clusters (OCs)== |
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Another powerful probe of galaxy evolution is provided by observing distant galaxies at high redshift. This allows us to see galaxies as they were long ago, and at various stages of their formation and evolution. Two important tracers of young galaxies are Lyman break galaxies and damped Lyman alpha systems. They are particularly useful probes of the formation and evolution of galaxies at earlier epochs, when the development of structure in the Universe was less advanced than it is today. |
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OCs have long been used to trace the structure and evolution of the Galactic disk. Open clusters have relatively large age & distance spans and can be relatively accurately dated; the spatial distribution, kinematical properties and metalicities of OCs provide critical constraints on the overall structure and chemical and dynamical evolution of the galactic disk; |
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Large scale galaxy surveys such as SDSS have released rich datasets. Group members have been involved in using these to investigate various statistical properties of observed galaxy populations, such as the structure and the stellar population of different galaxy types. |
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==Galactic Substructures== |
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Understanding how galaxy disks form is the key to understand how a galaxy forms. It is believed that disk dominated galaxies such as spirals are formed by the cooling of baryonic matter inside a virialized dark halo. Semi-analytic models (SAM) are a powerful tool in studying this process. The SAM method gives a detailed description of how the angular momentum in a protogalaxy is redistributed, how the disk grows, how star formation progresses, and can elucidate the role of galactic winds, and feedback, amongst many other effects. Researchers in the group have been actively involved in tackling these important research problems. |
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The present state of our galaxy can tell us a lot about how it has formed and evolved. In particular the stellar halo contains satellite galaxies and relics of accretion events, resulting in many substructures and streams. By discovering and analysing these substructures we can probe the details of hierarchical assembly and confront predictions from cosmological simulations. |
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==Galactic Chemical Evolution (GCE) model== |
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GCE is the study of the evolution in time and space of the abundances of the chemical elements in the interstellar medium (ISM) in galaxies. As the template of disk galaxies, the Milky Way galaxy is the best sample in testing the usefulness and importance of the GCE theory. By comparing the GCE results with the observations, we are able to understand how our Galaxy was assembled, what is the history of star formation and gas accretion during the evolution of the Galaxy. |
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==international collaborations== |
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One can learn more about our research from our [[publications]]. |
One can learn more about our research from our [[publications]]. |
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2014年9月9日 (二) 08:38的版本
Our research aims are to study the formation, evolution, and structure of galaxies. A central theme of the group’s research for many years has been stellar clusters and the structure of the Milky Way.
Stars and the Galactic structure
Characterising and classifying the stars around us is crucial if we are to use them to study the structure of our galaxy. Spectroscopic surveys such as LAMOST are providing spectra for millions of stars, but only by determining properties such as stellar types (and hence distances) and ages will we be fully able to exploit these datasets. Meanwhile, we are able to discover a large sample of Hyper-velocity stars, which will provide unique constraints on the shape of the potential of the Galaxy’s dark matter halo.
Open clusters (OCs)
OCs have long been used to trace the structure and evolution of the Galactic disk. Open clusters have relatively large age & distance spans and can be relatively accurately dated; the spatial distribution, kinematical properties and metalicities of OCs provide critical constraints on the overall structure and chemical and dynamical evolution of the galactic disk;
Galactic Substructures
The present state of our galaxy can tell us a lot about how it has formed and evolved. In particular the stellar halo contains satellite galaxies and relics of accretion events, resulting in many substructures and streams. By discovering and analysing these substructures we can probe the details of hierarchical assembly and confront predictions from cosmological simulations.
Galactic Chemical Evolution (GCE) model
GCE is the study of the evolution in time and space of the abundances of the chemical elements in the interstellar medium (ISM) in galaxies. As the template of disk galaxies, the Milky Way galaxy is the best sample in testing the usefulness and importance of the GCE theory. By comparing the GCE results with the observations, we are able to understand how our Galaxy was assembled, what is the history of star formation and gas accretion during the evolution of the Galaxy.
international collaborations
In addition to above research topics, we also have fruitful international co-operations with Germany (MPA), Canada (DAO), France (IAP), and the USA (UMASS) through visiting scholars, student exchanges, and joint observation programs.
One can learn more about our research from our publications.