Title: Observation and Evolution of Cold Gas, Star Formation and Galactic-scale Dark Matter in High-redshift Galaxies

Speaker：Daizhong Liu

Abstract: Galaxies are the fundamental building block of the Universe, but they show large varieties in morphology and physical properties and strong cosmic evolution. The cold gas, star formation processes, and dark matter haloes are all essential factors affecting their formation and evolution. In this talk, I will focus on the state-of-the-art observations of cold gas and star formation in high-redshift galaxies, and leveraging kinematic information from high-spatial-resolution observations to probe the galactic-scale dark matter properties at high redshift. I will highlight some of our efforts to exploit the science archive of the Atacama Large Millimeter Array, named the A³COSMOS project, and the largest contiguous deep field survey of the James Webb Space Telescope, known as the COSMOS-Web treasury survey. From these efforts, we obtain new understanding of how cold molecular gas fraction evolves with cosmic time from z~6 to present, how dark matter properties are constrained at cosmic noon, and what triggers high-redshift strong starbursty galaxies. These results indicate the importance of high-spatial-resolution spectro-imaging observations of large samples of high-redshift galaxies in order to obtain a precise knowledge on the (co)evolution of galaxies and dark matter.

Biography: Dr. Daizhong Liu is a Researcher at the Purple Mountain Observatory (PMO), Chinese Academy of Sciences. He obtained his Bachelor’s Degree from Nanjing University in 2010, and Ph.D. from PMO in 2016. He conducted post-doctoral research at Max-Planck-Institute for Astronomy from 2016 to 2020, and at Max-Planck-Institute for Extraterrestrial Physics from 2020 to 2024. His research interest includes submillimeter galaxies, cosmic star formation & ISM evolution, cold gas in galaxies, high-redshift galaxies and the early Universe, galaxy evolution, and gravitational lensing. His recent works involves cold gas and kinematics of high-redshift field and strongly-lensed galaxies, starburst and ISM in nearby circumnuclear disks, the development of the Chinese XSMT-15m submillimeter telescope, and the pioneer ultra-high-resolution terahertz Antarctic interferometry experiments. 

Time: 14:00-15:00, 18/November, Tuesday 

Venue: Room 506 (Large seminar room), Department of Astronomy 

You can also access the colloquium via: https://www.koushare.com/space/329883/live