Abstract We present the findings of a comprehensive and detailed analysis of merger tree data from ultra-high-resolution cosmological $N$-body simulations. The analysis, conducted with a particle mass resolution of $5 \times 10^3 h^{-1} M_{\odot}$ and a halo mass resolution of $10^7 h^{-1} M_{\odot}$, provides sufficient accuracy to suppress numerical artefacts....

Abstract The cold dark matter model predicts galaxies have 100 times more dark matter mass than stars. Nevertheless, recent observations report the existence of dark-matter-deficient galaxies with less dark matter than expected. To solve this problem, we investigate the physical processes of galaxy formation in head-on collisions between gas-containing dark...

In this research, a completely new method of Vlasov simulation was developed and adopted in a large-scale simulation of the motion of neutrinos in cosmological structure formation. The simulation was run on the entire system of supercomputer "Fugaku". Vlasov simulations can deliver noise-free numerical results compared to conventional N-body simulations,...

Supermassive black holes exist in the universe that are more than 100,000 times the mass of the Sun, and, although only a small part of them are luminous due to the energy of accreting material, in most galaxies, the central massive black hole is dark and quiet. The mechanism that...

In this research, we solved the Vlasov-Poisson equations directly by running our new high-precision numerical scheme for solving the Vlasov equation developed by the University of Tsukuba and the University of Tokyo on Japan's most powerful supercomputer, yielding 6-dimensional distributions of the neutrinos permeating our universe. This was the first...

Abstract Accurately solving the equations of radiative transfer for the radiation from stars and the interstellar medium is vital to underestanding the physics governing the interstellar medium, galaxy formation and evolution, and large-scale structure. Light from stars is absorbed and attenuated by neutral gas, but ultra-violet photons and those beyond...

Summary The research group consisting of postdoctoral fellow Takanobu Kirihara of the Graduate School of Pure and Applied Sciences, CCS postdoctoral fellow Yohei Miki, and led by CCS associate professor Masao Mori, has probed the dark matter*1 surrounding the Andromeda Galaxy*2 and found that the distribution of the dark matter...

Abstract Supermassive black holes (SMBH) have been observed in a large number of galaxies, but their origin and formation is still unkown. In the standard theory of galaxy formation, galaxies grow by successive mergers of smaller galaxies. If every galaxy had a black hole, then one could imagine that, after...