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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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

Masafusa Onoue

We present the latest observations of the early growth of active supermassive black holes (=quasars) in the early Universe, less than a billion years after the Big Bang, mainly using the Subaru Telescope and the James Webb Space Telescope (JWST). The search for distant quasars has been active since the Sloan Digital Sky Survey in the 2000s, with more than 300 reported so far. However, these are biased towards the brightest (=heaviest and most active) species in the early Universe, depending on the depth of survey observations. The Subaru Telescope's Hyper Suprime-Cam (HSC) wide-field survey, launched in 2014, is 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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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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ALMA and JWST exploration of high-redshift galaxies (and stars)

Extragalactic astronomy is currently in an exciting period. Observing high-redshift galaxies allows us to directly see galaxies...

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Cloud-scale molecular gas properties of nearby spiral and starburst galaxies with ALMA...

(Ultra)luminous infrared galaxies (= (U)LIRGs) at z=0 form stars 10-100 times more efficiently than z=0 main sequence...

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X線偏光観測による活動銀河核の構造

 Active Galactic Nucleus (AGN) is a phenomenon in which the accretion of mass onto a supermassive black...

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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