|Time:||星期一, 1月 03, 2022, 09:00am|
|Title:||Probing the Cosmic Reionization History and the Earliest SMBHs Using Distant Quasars|
|Speaker:||Dr. Jinyi Yang (Arizona)|
S727 & Online via Zoom
As the most luminous non-transit objects, quasars are unique probes of the early Universe. I have been leading a wide-field reionization-era quasar survey, which has provided the first large statistical sample of luminous quasars in the epoch of reionization, including the new redshift-record breaking quasar. I will first briefly introduce this survey and then present my recent works related to the reionization history and the early supermassive black holes (SMBHs). I build the largest optical spectral dataset of reionization-era quasar sightlines and measure the intergalactic medium (IGM) evolution through Ly-alpha/Ly-beta optical depth, transmission spikes, and quasar damping wings. My works suggest a rapid evolution of IGM effective optical depth up to z~6.1, highly neutral IGM at z > 7, and a patchy reionization process. With near-infrared spectra, I measure the BH masses and Eddington ratios and investigate the quasar UV spectral properties for a sample of quasars up to redshift 7.6. These quasars significantly challenge the models of SMBH growth and seed BHs, and the result is more consistent with a massive seed BH model. I will further lead several JWST and ALMA programs to investigate the early SMBHs and their host galaxies in great detail.
Jinyi Yang received her B.S. in 2011 from the University of Electronic Science and Technology of China and obtained her Ph.D. in astrophysics from Peking University in 2017. She joined the Steward observatory at the University of Arizona in 2017, first as a postdoctoral associate and then a Strittmatter fellow. Jinyi's research focuses on high-redshift quasar surveys and multi-wavelength observations of quasars. She is recently working on survey of the first quasars and the study of cosmic reionization history, the early supermassive black holes, and quasar host galaxies.
Host: Zheng Cai