About Us

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Our group strives to uncover the basic physics of star formation, planetary systems, active galactic nuclei, the birth of stars and galaxies of the early universe, the characteristics of the light they emit, formation and evolution of galaxies and black holes. We tackle many of the problems of modern astrophysics by solving equations of relativistic radiation hydrodynamics, radiation transport, and gravitational dynamics, which faithfully capture the interaction of light with matter and the complex gravitational interactions, so crucial in the study of the formation and evolution of stars, galaxies, and black holes. To find solutions to the complicated system of equations that describe multi-component celestial bodies and turbulent flow, we conduct large-scale numerical simulations, using, amongst others, tailor-made supercomputers at the Center for Computational Sciences.

Featured Articles

Frequency of the dark matter subhalo collisions and bifurcation sequence arising formation of dwarf galaxies

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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...

Recent Posts

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Star formation induced by cloud-cloud collisions in nearby barred galaxies

Yoshiomasa Watanabe

More than 300 molecular species have been identified in the interstellar matter. These chemical compositions provide various insights into the physical condition of molecular gas, its surrounding environment, and its evolution in the star and planet formation studies in the Galaxy. Thanks to the recent high sensitivity and high spatial resolution observations with ALMA, we can also apply the chemical approach to the star formation studies in the nearby galaxies. In this talk, we will present how cloud-cloud collisions affect star formation by using multi-line observations toward nearby barred spiral galaxies at a scale of sub-kpc with ALMA. In the...

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[Press release] The Cosmic Neutrino Background: World's First Six-dimensional Simulations

In this research, we solved the Vlasov-Poisson equations directly by running our new high-precision numerical scheme for...

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Theoretical and Observational Astrophysics Joint New Members BBQ

On the 3rd of May 2018, the Theoretical Astrophysics and the Observational Astrophysics groups organized a barbeque...

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38th National High School Cultural Festival in Ibaraki "Ibaraki Sobun 2014"

On July 28, 2014, Yu Komatsu was interviewed by students of the newspaper division of the 38th...

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State Transitions and Time Variations of Black Hole Accretion Flows

Black hole candidates display transitions between hard and soft X-ray states. During the transition, quasi-periodic oscillations and...

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A fierce new challenge: unveiling the connection between the first galaxies and...

The Epoch of Reionization (EoR) shaped the properties of the baryonic content of the Universe. Using hydrodynamical...

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Computing the Universe: from Intergalactic to Interstellar Medium

This talk will highlight some progress made based on our efforts of computing the universe, in order...

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Probing dust aggregate structure in protoplanetary disks by millimeter-wave polarization

Dust coagulation in protoplanetary disks is the first step of planetesimal formation. However, a pathway from dust...

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Formation of intermediate-mass black hole in forming star clusters

The existence of intermediate-mass black holes (IMBHs) in globular clusters has been debated. One possible way to...

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Volume density structure of the NGC 253 CMZ through ALCHEMI excitation analysis:...

NGC 253 is an archetypal starburst galaxy in the nearby universe, whose relative proximity (D ~ 3.5...

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すばる広視野サーベイとJWSTで見えてきた遠方超巨大ブラックホールの初期成長

We present the latest observations of the early growth of active supermassive black holes (=quasars) in the...

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磁気トルネード現象に注目した,太陽コロナ加熱のためのエネルギー発生・輸送・散逸の数値的研究

The outermost atmosphere of the Sun (the corona) reaches temperatures hundreds of times hotter than its surface...

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The grand meeting on black holes
~from stellar mass to super massive...

Almost 100 years after the prediction of general relativity, the existence of black holes has finally been...

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Formation of Astrophysical Objects 2023

This workshop aims to provide an opportunity to exchange views and share information about the current status...

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Black-hole jets, accretion discs, and disc-winds workshop 2023

Despite the fact that the existence of black holes is now firmly established, the structure and physical...

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Formation of Astrophysical Objects 2022

This workshop aims to provide an opportunity to exchange views and share information about the current status...

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Recent Work

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FOREVER22: Gas and metal outflow from massive galaxies in protocluster regions

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Generation of high circular polarization of interstellar Lyman α radiation triggering biological homochirality

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The formation of globular clusters with top-heavy initial mass functions

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FOREVER22: The first bright galaxies with population III stars at redshifts z 10-20 and comparisons with JWST data

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Cosmological-scale Lyα Forest Absorption around Galaxies and AGNs Probed with the HETDEX and SDSS Spectroscopic Data

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Morphologies of Galaxies at z 9 Uncovered by JWST/NIRCam Imaging: Cosmic Size Evolution and an Identification of an Extremely Compact Bright Galaxy at z 12