銀河におけるダストの物理的性質を理解することは，銀河形成・進化を解明する上で重要である。宇宙初期においては，重力崩壊型超新星 (Core-Collapse Supernova) がダスト供給の主要な起源であると考えられている。しかし，超新星の前方衝撃波が星間物質 (ISM) と相互作用することで発生する逆行衝撃波 (reverse shock) は，新たに形成されたダストを破壊し，その総質量を大幅に減少させる可能性がある。この破壊効率には依然として大きな不確実性が残されている。 本研究では，GR...
Present-day disk galaxies exhibit a two-layered structure, a thick disk and a thin disk. However, their structural growth history and dynamical properties across cosmic time remain to be understood. Leveraging JWST’s superb capability, we identify thin and thick stellar disks in galaxies up to 10 Gyr ago and measure their...
Quasi-periodic Eruption (QPE) は，系外銀河の中心でX線が数時間から数日周期でバーストを引き起こす現象である。これまでに10例程度発見されていてその 起源については諸説あるが，巨大ブラックホールの周囲を公転する星と降着円盤との衝突が有力である。最近の観測から，QPEが発生する数年前に同じ銀河で潮 汐破壊現象が起きていた証拠が得られており，QPEと関連する降着円盤は潮汐破壊現象を起源とすることが示唆されている。このような観測的示唆から，QPEは>潮汐破壊現象の発生・放射...
Planck, WMAP, and the Atacama Cosmology Telescope have recently reported a potential signal of cosmic birefringence, which refers to a rotation of the polarization plane, in the CMB polarization map (e.g. Eskilt & Komatsu 2022, Palazuelos & Komatsu 2025). This signal violates the parity symmetry of the Universe and, if...
Among the most energetic processes in the Universe, Active Galactic Nuclei (AGN) have been found throughout cosmic history; powered by a central Supermassive Black Hole (SMBH) with those at $z\gtrsim6$ being comparable in mass to SMBHs at $z\sim1$. The formation mechanism of SMBHs remains the subject of much debate, yet...
Roughly 10 billion years ago, during the Universe’s most active phase of star formation and black hole accretion, commonly known as Cosmic Noon, an extreme structure was discovered: a dense concentration of 11 luminous quasars within a comoving volume of $\sim 40$ cMpc$^3$ at redshift $z \approx 2.2$. This extreme...
ALMA and JWST have been pushing up the redshift frontier to z~14 and pioneering metal emission line studies in star-forming galaxies at $z > 5$. These telescopes are powerful tools for high-redshift probes even on their own, but their multi-wavelength synergy is opening a new window in the high-redshift studies....
The region within a radius of approximately 200 parsecs from the Galactic Center is known as the Central Molecular Zone (CMZ). This area is a dense concentration of molecular gas that is hotter, denser, and more turbulent than the gas in the galactic disk. The CMZ contains a large number...
銀河におけるダストの物理的性質を理解することは，銀河形成・進化を解明する上で重要である。宇宙初期においては，重力崩壊型超新星 (Core-Collapse Supernova) がダスト供給の主要な起源であると考えられている。しかし，超新星の前方衝撃波が星間物質 (ISM) と相互作用することで発生する逆行衝撃波 (reverse shock) は，新たに形成されたダストを破壊し，その総質量を大幅に減少させる可能性がある。この破壊効率には依然として大きな不確実性が残されている。 本研究では，GR...
July 2026 15 : 30 dust, supernovae, and high-z galaxies
Present-day disk galaxies exhibit a two-layered structure, a thick disk and a thin disk. However, their structural growth history and dynamical properties across cosmic time remain to be understood. Leveraging JWST’s superb capability, we identify thin and thick stellar disks in galaxies up to 10 Gyr ago and measure their...
May 2026 15 : 30 galactic disk, galaxy evolution, and hydrodynamics
Quasi-periodic Eruption (QPE) は，系外銀河の中心でX線が数時間から数日周期でバーストを引き起こす現象である。これまでに10例程度発見されていてその 起源については諸説あるが，巨大ブラックホールの周囲を公転する星と降着円盤との衝突が有力である。最近の観測から，QPEが発生する数年前に同じ銀河で潮 汐破壊現象が起きていた証拠が得られており，QPEと関連する降着円盤は潮汐破壊現象を起源とすることが示唆されている。このような観測的示唆から，QPEは>潮汐破壊現象の発生・放射...
April 2026 15 : 30 transients
Planck, WMAP, and the Atacama Cosmology Telescope have recently reported a potential signal of cosmic birefringence, which refers to a rotation of the polarization plane, in the CMB polarization map (e.g. Eskilt & Komatsu 2022, Palazuelos & Komatsu 2025). This signal violates the parity symmetry of the Universe and, if...
March 2026 15 : 30 CMB, AGN, and cosmology
Among the most energetic processes in the Universe, Active Galactic Nuclei (AGN) have been found throughout cosmic history; powered by a central Supermassive Black Hole (SMBH) with those at $z\gtrsim6$ being comparable in mass to SMBHs at $z\sim1$. The formation mechanism of SMBHs remains the subject of much debate, yet...
January 2026 15 : 30 AGN, early universe, and X-rays
Roughly 10 billion years ago, during the Universe’s most active phase of star formation and black hole accretion, commonly known as Cosmic Noon, an extreme structure was discovered: a dense concentration of 11 luminous quasars within a comoving volume of $\sim 40$ cMpc$^3$ at redshift $z \approx 2.2$. This extreme...
November 2025 15 : 30 quasars, large scale structure, and high-z galaxies
ALMA and JWST have been pushing up the redshift frontier to z~14 and pioneering metal emission line studies in star-forming galaxies at $z > 5$. These telescopes are powerful tools for high-redshift probes even on their own, but their multi-wavelength synergy is opening a new window in the high-redshift studies....
October 2025 15 : 30 ALMA, JWST, and high-z galaxies
The region within a radius of approximately 200 parsecs from the Galactic Center is known as the Central Molecular Zone (CMZ). This area is a dense concentration of molecular gas that is hotter, denser, and more turbulent than the gas in the galactic disk. The CMZ contains a large number...
September 2025 15 : 30 Galactic center, molecular clouds, and black holes
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