Quasars, luminous extra-galactic sources powered by accreting super-massive black holes (SMBH), have become increasingly important for probing the distant universe due to the growing number of spectroscopically confirmed quasars. My research focuses on exploring the statistical properties and evolution of quasars through careful analysis of their luminosity and black hole mass. In this talk, I will first present my findings on the quasar UV luminosity function at 3.5 < z < 5.0 using SDSS deep imaging data, which is a useful tool for studying the evolution of quasar spatial density. We suggest that the evolution of the QLFs from z ∼ 5 to 3.5 can be described by a pure density evolution model with a similar evolutional velocity to that at 5 < z < 7, indicating a nearly uniform evolution of the quasar density at z = 3.5–7. In the second part of my talk, I will discuss how I build a large and well-designed quasar sample at 0.2 < z < 0.8 from DESI to systematically study and compare different single-epoch black hole mass tracers. By deriving iron-corrected R-L relations, we are able to improve Hβ- and MgII-based SMBH mass estimations, taking the accretion state into consideration. These findings contribute to a better understanding of the properties and evolution of quasars and have implications for broader questions regarding the coevolution of quasars and host galaxies.
BIO
Zhiwei Pan is a 4th-year PhD student in Prof. Linhua Jiang's group at KIAA, PKU. His primary research interests lie in statistical analysis of large quasar samples, including investigations into quasar luminosity function, black hole mass function, and related topics.
Host: Xiaojing Lin
