Cosmology, Galaxy Formation and Evolution

The research of our division on cosmology, galaxy formation and evolution includes the following directions:

 Cosmic dawn and reionization detection, large-scale structure of the universe

1. The cosmic dawn and reionization is an important period in the cosmic evolution, in which the first generation of stars and galaxies formed. We have little idea about what happened in this period. Researchers in our division use radio telescopes, such as 21CMA, MWA and the forthcoming SKA, to detect neutral hydrogen during this period. At the same time, we are performing 21cm global signal detection experiment in China. The main researchers in this direction include ZHENG Qian, SHAN Huan-yuan, GUO Quan, ZHANG Jia-jun and WANG Jing-ying, etc.

2. The formation and evolution of the large-scale structure of the universe is a hot topic in modern cosmology. Using the third-generation sky surveys (KiDS, DES and HSC) and the fourth-generation sky surveys (DESI and the Chinese Space Station Survey Telescope CSST, etc.), researchers in our division use strong and weak gravitational lensing, baryon acoustic oscillations, galaxy clusters and other probes to uncover the large-scale structure of the universe, study the nature of dark matter and dark energy. The main researchers in this direction include SHAN Huan-yuan, ZHAN Jia-jun, GUO Hong, WANG Peng, etc.

3. The observation and research of galaxies in the early universe, especially in the reionization period of the universe, is a hot frontier field of astrophysics. This involves the formation of the first generation of galaxies and black holes in the universe. It is also one of the core scientific goals of CSST. Researchers in this direction include ZHENG Zhen-ya, YUAN Fang-ting, JIANG Chun-yan, etc.

Dark matter halo, galaxy distribution and large-scale structure

1. Statistical studies of Large-sample galaxies are powerful tools for revealing the physical properties of galaxies. Combined with the statistical characteristics of dark halos given by N-body numerical simulations, a semi-analytical model of galaxy formation and evolution can be constructed based on the observed statistical properties of galaxies. Researchers in this direction include ZHAO Dong-hai, SHEN Shi-yin, GUO Hong, FU Jian, etc.

2. The large-scale environment is the formation stage of galaxy, where galaxies gain gas, angular momentum, and merge with satellite galaxies. Studying the correlation between large-scale structures and galaxies will help shed light on the formation of cosmic structures, and how they affect galaxy formation. Researchers in this direction include GUO Hong, WANG Peng, ZHANG You-cai, GUO Quan, etc.

 Observational characteristics of galaxies

The multi-band observational data and properties of galaxies contain rich information of galaxy formation and evolution. Integral field-of-view spectroscopic observations of galaxies are ideal data for simultaneously studying three-dimensional features (space and wavelength) of galaxies. Building an essential field of view spectrometer on a space telescope and carrying out related scientific research simultaneously is the standard research direction of several research groups in the Space Room. The relevant researchers include HAO Lei, SHAO Zhengyi, SHEN Shi-yin, ZHU Ling, etc. 

 Observational characteristics of active galactic nuclei

1. Observational Characteristics (from radio up to gamma-rays) of Active Galactic Nuclei. The relevant researchers include GU Min-feng, HAO Lei, and associated member in SHAO AN Tao.

2. Observational Co-evolution of galaxies and active galactic nuclei. The relevant researchers include HAO Lei and SHEN Shi-yin.

 Galaxy structure, evolution and dynamics

1. Galaxy formation and evolution on galactic scales: We utilize large-scale numerical hydrodynamic simulations to investigate the formation and evolution of galaxies under the combined action of AGN feedback and stellar feedback, as well as the impact of magnetic field, turbulence, cosmic rays, dust, etc. on the interstellar medium, circumgalactic medium and galaxy evolution. Researchers in this direction include YUAN Feng, GUO Fulai, JI Suoqing and LI Yaping.

2. Chemical evolution of galaxies: The model of chemical evolution of galaxies is an important tool for studying the metal enrichment process of the gas in galaxies and the history of star formation. This direction is to study the spatial distribution of stars and gas in galaxies (especially the Milky Way) and their evolution over time, the metal abundance of gas and the evolution of stellar population characteristics over time. Researchers in this direction include HOU Jinliang, CHANG Ruixiang and ZHU Ling.

3. The dynamic structure of galaxies is the fossil of the history of galaxy formation, reflecting important information such as merging events. At the same time, dynamics is also an important probe for the distribution of dark matter in galaxies and the mass of central black holes. Researchers in this direction include ZHU Ling.

4.The dynamics and chemical evolution models of galaxies can describe the detailed features of galaxy evolution. The observed properties of nearby galaxies with rich structural, kinematics and chemical characteristics can effectively constrain the dynamics and chemical evolution models of galaxies. Researchers in this direction include HOU Jinliang, ZHU Ling and CHANG Ruixiang.

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