Star Formation in Self-gravitating Disks in Active Galactic Nuclei. III. Efficient Production of Iron and Infrared Spectral Energy Distributions
Strong iron lines are a common feature of the optical spectra of active galactic nuclei (AGNs) and quasars from z ∼ 6−7 to the local universe, and [Fe/Mg] ratios do not show cosmic evolution. During active episodes, accretion disks surrounding supermassive black holes (SMBHs) inevitably form stars i...
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| Format: | Article |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/acdf48 |
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| author | Jian-Min Wang Shuo Zhai Yan-Rong Li Yu-Yang Songsheng Luis C. Ho Yong-Jie Chen Jun-Rong Liu Pu Du Ye-Fei Yuan |
| author_facet | Jian-Min Wang Shuo Zhai Yan-Rong Li Yu-Yang Songsheng Luis C. Ho Yong-Jie Chen Jun-Rong Liu Pu Du Ye-Fei Yuan |
| author_sort | Jian-Min Wang |
| collection | DOAJ |
| description | Strong iron lines are a common feature of the optical spectra of active galactic nuclei (AGNs) and quasars from z ∼ 6−7 to the local universe, and [Fe/Mg] ratios do not show cosmic evolution. During active episodes, accretion disks surrounding supermassive black holes (SMBHs) inevitably form stars in the self-gravitating part, and these stars accrete with high accretion rates. In this paper, we investigate the population evolution of accretion-modified stars (AMSs) to produce iron and magnesium in AGNs. The AMSs, as a new type of star, are allowed to have any metallicity but without significant loss from stellar winds, since the winds are choked by the dense medium of the disks and return to the core stars. Mass functions of the AMS population show a pile-up or cutoff pile-up shape in top-heavy or top-dominant forms if the stellar winds are strong, consistent with the narrow range of supernovae (SNe) explosions driven by the known pair-instability. This provides an efficient way to produce metals. Meanwhile, SN explosions support an inflated disk as a dusty torus. Furthermore, the evolving top-heavy initial mass functions lead to bright luminosity in infrared bands in dusty regions. This contributes a new component in infrared bands, which is independent of the emissions from the central part of accretion disks, appearing as a long-term trending of the NIR continuum compared to optical variations. Moreover, the model can be further tested through reverberation mapping of emission lines, including LIGO/LISA detections of gravitational waves and signatures from spatially resolved observations of GRAVITY+/VLTI. |
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| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T02:57:04Z |
| publishDate | 2023-01-01 |
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| series | The Astrophysical Journal |
| spelling | doaj.art-602ebfc79e694dc482c4ef674491e3762023-09-03T15:13:47ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0195418410.3847/1538-4357/acdf48Star Formation in Self-gravitating Disks in Active Galactic Nuclei. III. Efficient Production of Iron and Infrared Spectral Energy DistributionsJian-Min Wang0https://orcid.org/0000-0001-9449-9268Shuo Zhai1Yan-Rong Li2https://orcid.org/0000-0001-5841-9179Yu-Yang Songsheng3https://orcid.org/0000-0003-4042-7191Luis C. Ho4https://orcid.org/0000-0001-6947-5846Yong-Jie Chen5https://orcid.org/0000-0003-4280-7673Jun-Rong Liu6Pu Du7https://orcid.org/0000-0002-5830-3544Ye-Fei Yuan8https://orcid.org/0000-0002-7330-4756Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences , 19B Yuquan Road, Beijing 100049, People's Republic of China; School of Astronomy and Space Sciences, University of Chinese Academy of Sciences , 19A Yuquan Road, Beijing 100049, People's Republic of China; National Astronomical Observatory of China , 20A Datun Road, Beijing 100020, People's Republic of ChinaKey Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences , 19B Yuquan Road, Beijing 100049, People's Republic of China; School of Physical Sciences, University of Chinese Academy of Sciences , 19A Yuquan Road, Beijing 100049, People's Republic of ChinaKey Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences , 19B Yuquan Road, Beijing 100049, People's Republic of ChinaKey Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences , 19B Yuquan Road, Beijing 100049, People's Republic of ChinaKavli Institute for Astronomy and Astrophysics, Peking University , Beijing 100871, People's Republic of China; Department of Astronomy, School of Physics, Peking University , Beijing 100871, People's Republic of ChinaKey Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences , 19B Yuquan Road, Beijing 100049, People's Republic of China; School of Physical Sciences, University of Chinese Academy of Sciences , 19A Yuquan Road, Beijing 100049, People's Republic of ChinaKey Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences , 19B Yuquan Road, Beijing 100049, People's Republic of China; School of Physical Sciences, University of Chinese Academy of Sciences , 19A Yuquan Road, Beijing 100049, People's Republic of ChinaKey Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences , 19B Yuquan Road, Beijing 100049, People's Republic of ChinaDepartment of Astronomy, University of Science and Technology of China , Hefei 230026, People's Republic of ChinaStrong iron lines are a common feature of the optical spectra of active galactic nuclei (AGNs) and quasars from z ∼ 6−7 to the local universe, and [Fe/Mg] ratios do not show cosmic evolution. During active episodes, accretion disks surrounding supermassive black holes (SMBHs) inevitably form stars in the self-gravitating part, and these stars accrete with high accretion rates. In this paper, we investigate the population evolution of accretion-modified stars (AMSs) to produce iron and magnesium in AGNs. The AMSs, as a new type of star, are allowed to have any metallicity but without significant loss from stellar winds, since the winds are choked by the dense medium of the disks and return to the core stars. Mass functions of the AMS population show a pile-up or cutoff pile-up shape in top-heavy or top-dominant forms if the stellar winds are strong, consistent with the narrow range of supernovae (SNe) explosions driven by the known pair-instability. This provides an efficient way to produce metals. Meanwhile, SN explosions support an inflated disk as a dusty torus. Furthermore, the evolving top-heavy initial mass functions lead to bright luminosity in infrared bands in dusty regions. This contributes a new component in infrared bands, which is independent of the emissions from the central part of accretion disks, appearing as a long-term trending of the NIR continuum compared to optical variations. Moreover, the model can be further tested through reverberation mapping of emission lines, including LIGO/LISA detections of gravitational waves and signatures from spatially resolved observations of GRAVITY+/VLTI.https://doi.org/10.3847/1538-4357/acdf48Active galactic nucleiGalaxy accretion disksSupermassive black holes |
| spellingShingle | Jian-Min Wang Shuo Zhai Yan-Rong Li Yu-Yang Songsheng Luis C. Ho Yong-Jie Chen Jun-Rong Liu Pu Du Ye-Fei Yuan Star Formation in Self-gravitating Disks in Active Galactic Nuclei. III. Efficient Production of Iron and Infrared Spectral Energy Distributions The Astrophysical Journal Active galactic nuclei Galaxy accretion disks Supermassive black holes |
| title | Star Formation in Self-gravitating Disks in Active Galactic Nuclei. III. Efficient Production of Iron and Infrared Spectral Energy Distributions |
| title_full | Star Formation in Self-gravitating Disks in Active Galactic Nuclei. III. Efficient Production of Iron and Infrared Spectral Energy Distributions |
| title_fullStr | Star Formation in Self-gravitating Disks in Active Galactic Nuclei. III. Efficient Production of Iron and Infrared Spectral Energy Distributions |
| title_full_unstemmed | Star Formation in Self-gravitating Disks in Active Galactic Nuclei. III. Efficient Production of Iron and Infrared Spectral Energy Distributions |
| title_short | Star Formation in Self-gravitating Disks in Active Galactic Nuclei. III. Efficient Production of Iron and Infrared Spectral Energy Distributions |
| title_sort | star formation in self gravitating disks in active galactic nuclei iii efficient production of iron and infrared spectral energy distributions |
| topic | Active galactic nuclei Galaxy accretion disks Supermassive black holes |
| url | https://doi.org/10.3847/1538-4357/acdf48 |
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