Detection of the Circumgalactic Medium of Nearby Galaxies via Emission Lines
报告人
张华年（华中科技大学）
报告时间
2021年12月21日 16:00
主办方
中国科学技术大学天文学系
直播二维码
报告人介绍
Huanian Zhang (huanian@hust.edu.cn) is an associate professor at Astronomy Department, Huazhong University of Science and Technology. Prof. Zhang got his bachelor from Shandong University in 2011, and PhD from University of Arizona in 2016. After obtaining the PhD, Prof. Zhang moved from the physics building to the astronomy building just a few blocks away. Huanian’s main focus is on probing the Circumgalactic Medium (CGM). He had the first detection of CGM of nearby galaxies up to 100 kpc via Halpha and [NII] emission lines. Other than the CGM study, Huanian is also working on the all-sky search for globular clusters in the Local Volume using combined datasets of Decals, WISE and Galex, on studying the Milky Way halo structure using halo stars up to 100 kpc and on the study of cross correlation between high redshift galaxies and QSOs.
报告摘要
Galaxies are surrounded by diffuse and extended gas, which is often called the circumgalactic medium (CGM) and is the least understood part of galactic ecosystems. The CGM harbors more than 80% of the total baryons in a galaxy, is both the reservoir of gas for subsequent star formation and the depository of chemically processed gas, energy, and angular momentum from feedback. Observations and simulations of the CGM suggest that it is a multi-phase medium characterized by rich dynamics and complex ionization states. The study of the CGM has so far generally come from absorption line studies of the spectra of distant objects, typically QSOs, whose lines of sight intersect lower redshift galaxy halos. However, such study is limited by statistics. Instead, I will describe a novel approach to study the CGM via emission lines, which allows for direct mapping of individual galaxies and a variety of results obtained.