Kohei Inayoshi, Ph.D.

Kohei Inayoshi received his bachelor’s and master’s degrees in physics from Kyoto University, Japan. He obtained his Ph.D. in physics from Kyoto University in 2014 and currently works at Columbia University as a JSPS research fellow.

His research focuses on supermassive black holes (SMBHs), which are extremely huge objects at the center of most galaxies possessing masses between millions to tens of billions of times that of the Sun. Such SMBHs are observed at the early epoch of the Universe, and the fact that SMBHs form and grow quickly gives a strong constraint on their formation process. One promising solution to this puzzle is the formation of massive seed black holes through the gravitational collapse of supermassive stars.

He studied the necessary conditions for supermassive star formation. Using hydrodynamical simulations, he showed for the first time that a primordial gas cloud undergoes runaway collapse without a major episode of fragmentation and forms a supermassive star if certain necessary conditions are satisfied. The results will be useful to understand the grand picture of SMBH evolution across the cosmic time.