Frontier Research Institute for Interdisciplinary Sciences
Tohoku University

Galaxies across the universe appear to host a central supermassive black holes (SMBHs), typically 10^6 to 10^10 times the mass of the Sun, and even the Milky Way harbors the one.
Yet some quasars already exceed a billion solar masses less than a billion years after the Big Bang, raising fundamental questions: How did the first “seeds” form? How fast can SMBHs grow? And how does this growth shape their host galaxies?

Active galactic nuclei (AGN), SMBHs actively accreting gas, offer a direct window into these processes. My group focuses on two complementary wavelength regimes that most cleanly trace SMBH growth. X-rays originate near the black hole and penetrate obscuring gas, providing a near-instantaneous measure of accretion power. Infrared (IR) emission arises from dust heated by the central engine, revealing the amount and distribution of material that can sustain future activity. By combining X-ray and IR observations, we can connect “how much is being accreted now” to “how much fuel remains.”

We apply this approach across cosmic time, integrating large surveys and pointed observations (e.g., space-based X-ray data and ground/space IR imaging and spectroscopy). The goal is a physically consistent picture of SMBH growth and its impact on galaxies, from the early universe to the present day.