Abstract

The most distant luminous quasars provide unique probes to the formation of the earliest supermassive black holes (SMBHs), the assembly of massive galaxies and the reionization of intergalactic medium. In this talk, I will review the ongoing quasar surveys which yield a sizable sample of quasars at redshift z~7 and several luminous quasars at redshift beyond 7.5, deep into the epoch of reionization. These quasar surveys allow the first measurement of quasar luminosity function and the characterization of quasar evolution in the reionization-era. In addition, the existence of billion solar mass black holes at redshift beyond 7.5 posts stringent constraints on the theory of black hole formation and growth in the early Universe. I will also present our projects for investigating quasar host galaxies using high resolution ALMA observations and studying the large-scale environment of the earliest SMBHs with deep wide field imaging.