Location: Multifunctional Hall on the 5th floor Meeting time: 2021/05/19 14:00-15:00 (CST)

Speaker: Gang Zhao (NAOC)

Research on the fusion of the Milky Way based on the LAMOST Sky Survey

Gang Zhao

Abstract

The study of galactic merger is one of the important frontiers of astrophysics. The discovery of stellar streams led people to believe that the Milky Way was mainly formed by merging nearby dwarf galaxies. These dwarf galaxies were disintegrated by the strong tidal force of the Milky Way to form star streams. These star streams provided key observational evidence for the formation of the Milky Way. Theoretical simulations indicate that there may be hundreds of star streams in the Milky Way, but only a dozen kinematic clusters of star streams have been found in observations. The huge difference in the number of star streams between observations and theories makes the formation of the Milky Way complicated and confusing. Using the LAMOST sky survey data, we found a batch of star streams originating from the merging process of the Milky Way. These newly discovered star streams not only narrowed the gap between theory and observations to a certain extent, but also confirmed that the tidal stream collapsed after a billion years of evolution can still find traces of their common origin in the kinematic space. This opens up a new way to use large-scale spectral survey data to detect star streams in kinematic space and chemical space.

Bio

Researcher of the National Astronomical Observatory of the Chinese Academy of Sciences, doctoral supervisor. He is currently a member of the scientific organization committee of the International Astronomical Union “The Local Universe” and the director of the LAMOST scientific committee. He has won the second prize of the National Natural Science Award, the He Liang He Li Science and Technology Progress Award, the Huang Runqian Astrophysics Fundamental Research Award, and the Hong Kong Qiushi Outstanding Scientific and Technological Achievement Collective Award. He is currently the project leader of the “Basic Science Center” of the National Natural Science Foundation of China and the chief scientist of the National Key Research and Development Program “Galactic Research Based on LAMOST Sky Survey”.