Title: Probing Protoclusters and Galaxy Mergers during the Epoch of Reionization with JWST

Time: Wednesday (12.04) morning 10-11am

Location: the middle conference room, 3rd floor

Speaker: Qiong Li (李琼), University of Manchester

Abstract: JWST has produced a revolution in using photometric redshifts and/or multi-colour selection criteria to find galaxies at the extreme redshifts, offering a unique opportunity to answer questions regarding the formation of galaxies in the early Universe. In this talk, I’ll present our latest discovery of protoclusters and mergers during the Epoch of Reionization using JWST. We'll discuss the environmental effects on these galaxies' properties and characteristics, such as their stellar mass history, star formation activities, and interstellar medium properties. Furthermore, I will show how we use NIRCam deep imaging data for a quantitative study of the galaxy environment. It is the first systematic investigation of high-redshift mergers and their evolution with redshift at z>5. On a larger scale, I will introduce the study of high-redshift clustering, mapping the Universe's dense regions on the Mpc scale. We have also quantitatively identified potential protocluster candidates. This marks the first step in identifying protoclusters within JWST’s wide field based on photometric data, offering valuable insights to advance our understanding of cosmic structure formation in the early Universe. AGNs consistently coexist with dense galaxy environments. I will also show how the combination of NIRCam and deep MIRI photometry offers a reliable method for AGN identification.

Biography: Dr. Qiong Li is currently a postdoc researcher at the University of Manchester. She received her PhD degree in 2020 at Peking University. Her recent research focuses on using JWST photometric and spectroscopic data to study first-generation galaxies and their environments.