"Quest for the First Galaxies in the Universe"

Abstract: Finding and characterizing the earliest systems are pivotal for answering critical cosmological questions such as the emergence of first galaxies and black holes (BHs), as well as the cosmic reionization process. The advent of JWST has advanced our capability to detect and analyze systems from the early galaxies, now serving the candidates out to z~17. Simultaneously, submm/mm observations have gained prominence, providing complementary insights into the cold dust and gas characteristics and verifying the authenticity of ultra-high-redshift galaxy candidates against dusty lower-redshift interlopers. In the colloquium talk, I will overview my recent quest for the first light in the universe. My strategy synergizes JWST, ALMA, and Gravitational Lensing for the most sensitive and comprehensive investigations of the earliest epochs. My systematic JWST spectroscopic survey corroborates the high abundance of z > 9 galaxies recently claimed from photometric measurements, and I will discuss its possible origins from their initial characterizations. I also derive the infrared luminosity function by establishing the largest faint ALMA mm sample ever, enabling the first direct attempt to quantify the total (=unobscured + dust-obscured) cosmic star formation history up to z~8. Looking ahead, I will also present my vision in the next few years to decades, introducing wide survey and timely follow-up plans to scout out the first emergence of stars and dust, leveraged by current and upcoming facilities such as JWST, Euclid, Roman, Subaru/PFS, ALMA, and CCAT-prime.