Abstact: With the start of JWST's science operations, observational studies of the cosmic dawn have advanced significantly, reaching redshifts as high as ~15. These studies have revealed surprising and unexpected results, although further observations and validation remain essential. In this talk, I will showcase recent progress in early galaxy observations, focusing on key properties of galaxies and their interstellar medium (ISM), including chemical abundances, metallicities, abundance ratios, galaxy morphologies, feedback processes, and the emergence of supermassive black holes, as well as their connections to little red dots. Finally, I will discuss the role of these early galaxies in cosmic reionization and explore the implications for cosmology by combining JWST findings with complementary results from other major ground- and space-based facilities.
Short Bio: Masami Ouchi is a Professor at the National Astronomical Observatory of Japan (NAOJ) and the University of Tokyo. His research focuses on observational cosmology and galaxy formation, particularly the formation and evolution of the earliest galaxies and cosmic reionization. He conducts observational studies using major ground- and space-based telescopes, including Subaru, ALMA, and JWST, to investigate the physical properties of early galaxies, the interstellar and intergalactic media, and the evolution of the early universe.