Title: The variable stellar initial mass function and the coming survey with CSST

Speaker: 刘超

Institute:  国家天文台

Host: 冯思轶

Time: 12.7 周四 14:30-16:30

Location: 物理楼552

Abstract: 

The stellar initial mass function (IMF) is one of the most important distribution in astrophysics in the sense that it plays crucial roles from star formation to galactic evolution. For a long time, astronomers assumed that IMF is universal in the universe. I will talk about our recent finding that IMF varies depends on both metallicity and stellar age based on star-counting statistics using ~93,000 LAMOST and Gaia observed M-dwarf stars, more than an order of magnitude larger than previous studies, in the 100--300 parsec Solar neighbourhood. I will also show some new measurements, from the Milky Way to Andromeda, which may give more insight of the nature of the IMF. In about two years, Xuntian space telescope (CSST) will be launched and start its 10-year survey journey. I will give a brief introduction to this flagship space-borne astronomical facility and discuss its potential in understanding the stellar IMF in the nearby galaxies as well as in the Milky Way. In any aspect, CSST may challenge our ordinary way of research since it will provide at least 30 PB images, spectra, and catalogs. Among these data, we are able to identify tens of billion galaxies and almost the same number of stars. I will finally highlight an idea about how to deal with these large data with new technology from computer science.

Bio：

Liu Chao obtained his PhD degree in 2008 at NAOC. Then he went to Max Planck Institute for Astronomy in Germany as a postdoc since 2009. He was leading the development of GSP-PHOT, the stellar parametrization software package, in Gaia Data Processing and Analysis Consortum (DPAC) during his stay in Germany. In 2012, he went back to NAOC as a faculty member and get involved in a number of studies using LAMOST survey data. His interests of science include stellar physics, the stellar populations, the Milky Way, Galactic dynamics etc. He is now a professor of NAOC, professor of the University of CAS, and researcher at the Institute for frontiers in Astronomy and Astrophysics at Beijing Normal University. He is the chief designer of the data processing and analysis system of CSST.