97 research outputs found
Pulsation-driven Mass Loss from Massive Stars behind Stellar Mergers in Metal-poor Dense Clusters
No full textMESA inlists, run_star_extras, and data associated with Nakauchi, Inayoshi, Omukai 2020. MESA version
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Autophagy is suppressed by low temperatures and is dispensable for cold acclimation in Arabidopsis
No full textCitation: Akito Sato, Sena Inayoshi, Kohei Kitawaki, Ryota Mihara, Kosei Yoneda, Yasuko Ito‐Inaba, Takehito Inaba, Autophagy is suppressed by low temperatures and is dispensable for cold acclimation in Arabidopsis, Physiologia Plantarum, 176(4), 2024-07, https://doi.org/10.1111/ppl.1440
Formation pathway of Population III coalescing binary black holes through stable mass transfer
No full text<p>MESA inlists associated with <a href="https://ui.adsabs.harvard.edu/?#abs/2017MNRAS.468.5020I">Inayoshi et al. (2017)</a>. MESA version 8845.</p>
<p>Publication DOI: <a href="https://doi.org/10.1093/mnras/stx757">10.1093/mnras/stx757</a></p>
宇宙初期の超巨大ブラックホール形成
No full text京都大学0048新制・課程博士博士(理学)甲第18065号理博第3943号新制||理||1568(附属図書館)30923京都大学大学院理学研究科物理学・宇宙物理学専攻(主査)教授 中村 卓史, 教授 鶴 剛, 教授 畑 浩之学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDFA
Extremely Dense Gas around Little Red Dots and High-redshift Active Galactic Nuclei: A Nonstellar Origin of the Balmer Break and Absorption Features
No full textThe James Webb Space Telescope (JWST) has uncovered low-luminosity active galactic nuclei (AGNs) at high redshifts of z ≳ 4–7, powered by accreting black holes with masses of ∼10 ^6−8 M _⊙ . One remarkable distinction of these JWST-identified AGNs, compared to their low-redshift counterparts, is that at least ∼20% of them present H α and/or H β absorption, which must be associated with extremely dense (≳10 ^9 cm ^−3 ) gas in the broad-line region or its immediate surroundings. These Balmer absorption features unavoidably imply the presence of a Balmer break caused by the same dense gas. In this Letter, we quantitatively demonstrate that a Balmer break can form in AGN spectra without stellar components, when the accretion disk is heavily embedded in dense neutral gas clumps with densities of ∼10 ^9−11 cm ^−3 , where hydrogen atoms are collisionally excited to the n = 2 states and effectively absorb the AGN continuum at the bluer side of the Balmer limit. The nonstellar origin of a Balmer break offers a potential solution to the large stellar masses and densities inferred for little red dots (LRDs) when assuming that their continuum is primarily due to stellar light. Our calculations indicate that the observed Balmer absorption blueshifted by a few hundred km s ^−1 , which suggests the presence of dense outflows in the nucleus at rates exceeding the Eddington value. Other spectral features such as higher equivalent widths of broad H α emission and presence of O i lines observed in high-redshift AGNs including LRDs align with the predicted signatures of a dense super-Eddington accretion disk
Universal Transition Diagram from Dormant to Actively Accreting Supermassive Black Holes
No full text学術論文(Ariticle)journal articl
Light, medium-weight or heavy? The nature of the first supermassive black hole seeds
No full textObservations of hyper-luminous quasars at z>6 reveal the rapid growth of supermassive black holes (SMBHs >10^9 m M_{odot}) whose origin is still difficult to explain. Their progenitors may have formed as remnants of massive, metal free stars (light seeds), via stellar collisions (medium-weight seeds) and/or massive gas clouds direct collapse (heavy seeds). In this work we investigate for the first time the relative role of these three seed populations in the formation of z>6 SMBHs within an Eddington-limited gas accretion scenario. To this aim, we implement in our semi-analytical data-constrained model a statistical description of the spatial fluctuations of Lyman-Werner (LW) photo-dissociating radiation and of metal/dust enrichment. This allows us to set the physical conditions for BH seeds formation, exploring their relative birth rate in a highly biased region of the Universe at z>6. We find that the inclusion of medium-weight seeds does not qualitatively change the growth history of the first SMBHs: although less massive seeds (<10^3 m M_odot) form at a higher rate, the mass growth of a SMBH at z<15 is driven by efficient gas accretion (at a sub-Eddington rate) onto its heavy progenitors (). This conclusion holds independently of the critical level of LW radiation and even when medium-weight seeds are allowed to form in higher metallicity galaxies, via the so-called super-competitive accretion scenario. Our study suggests that the genealogy of SMBHs is characterized by a rich variety of BH progenitors, which represent only a small fraction (< 10 - 20%) of all the BHs that seed galaxies at z > 15
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