The extremes of continuum and emission-line variability of AGN: Changing-look events and binary SMBHS
The extremes of emission-line and continuum variability of Active Galactic Nuclei (AGN) are unique probes of the physics and geometry of the central engine. This review provides an overview of the most extreme cases of continuum and optical emission-line variability of AGN and the proposed...
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| Language: | English |
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Astronomical Observatory, Department of Astronomy, Belgrade
2024-01-01
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| Series: | Serbian Astronomical Journal |
| Subjects: | |
| Online Access: | https://doiserbia.nb.rs/img/doi/1450-698X/2024/1450-698X2409001K.pdf |
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| author | Komossa S. Grupe D. |
| author_facet | Komossa S. Grupe D. |
| author_sort | Komossa S. |
| collection | DOAJ |
| description | The extremes of emission-line and continuum variability of Active Galactic
Nuclei (AGN) are unique probes of the physics and geometry of the central
engine. This review provides an overview of the most extreme cases of
continuum and optical emission-line variability of AGN and the proposed
interpretations. We also point out remaining challenges in the identification
of changing-look (CL) AGN and discuss future prospects. This includes the
need for identification of larger samples of CL narrow-line Seyfert 1
galaxies and CL LINERs at opposite ends of the accretion regime. In the
second part, evidence for semi-periodic variability of broad lines and
continuum emission, and its possible interpretation by the presence of
binary SMBHs is addressed. Most recent results from the project MOMO are
presented which monitors densely the best-known binary SMBH candidate OJ
287. In the last few years, the results from this project have ruled out the
leading binary model and clearly established the need for new binary
modeling in an entirely different parameter regime and based on the actually
measured (primary) SMBH mass of 108 M⊙. Ongoing and near-future time-domain
surveys, and first gravitational wave detections of single systems, will play
an important role in advancing this frontier in astrophysics. |
| format | Article |
| id | doaj-art-2af08a7677734ef584ca93af4bbe4092 |
| institution | Kabale University |
| issn | 1450-698X 1820-9289 |
| language | English |
| publishDate | 2024-01-01 |
| publisher | Astronomical Observatory, Department of Astronomy, Belgrade |
| record_format | Article |
| series | Serbian Astronomical Journal |
| spelling | doaj-art-2af08a7677734ef584ca93af4bbe40922025-08-20T03:58:44ZengAstronomical Observatory, Department of Astronomy, BelgradeSerbian Astronomical Journal1450-698X1820-92892024-01-01202420912410.2298/SAJ2409001K1450-698X2409001KThe extremes of continuum and emission-line variability of AGN: Changing-look events and binary SMBHSKomossa S.0https://orcid.org/0000-0003-4183-4215Grupe D.1https://orcid.org/0000-0002-9961-3661Max-Planck-Institut für Radioastronomie, Bonn, GermanyDepartment of Physics, Geology, and Engineering Technology, Northern Kentucky University, Nunn Drive, Highland Heights, USAThe extremes of emission-line and continuum variability of Active Galactic Nuclei (AGN) are unique probes of the physics and geometry of the central engine. This review provides an overview of the most extreme cases of continuum and optical emission-line variability of AGN and the proposed interpretations. We also point out remaining challenges in the identification of changing-look (CL) AGN and discuss future prospects. This includes the need for identification of larger samples of CL narrow-line Seyfert 1 galaxies and CL LINERs at opposite ends of the accretion regime. In the second part, evidence for semi-periodic variability of broad lines and continuum emission, and its possible interpretation by the presence of binary SMBHs is addressed. Most recent results from the project MOMO are presented which monitors densely the best-known binary SMBH candidate OJ 287. In the last few years, the results from this project have ruled out the leading binary model and clearly established the need for new binary modeling in an entirely different parameter regime and based on the actually measured (primary) SMBH mass of 108 M⊙. Ongoing and near-future time-domain surveys, and first gravitational wave detections of single systems, will play an important role in advancing this frontier in astrophysics.https://doiserbia.nb.rs/img/doi/1450-698X/2024/1450-698X2409001K.pdfgalaxies: nucleigalaxies: seyfertquasars: emission linesquasars: supermassive binary black holesaccretion disks |
| spellingShingle | Komossa S. Grupe D. The extremes of continuum and emission-line variability of AGN: Changing-look events and binary SMBHS Serbian Astronomical Journal galaxies: nuclei galaxies: seyfert quasars: emission lines quasars: supermassive binary black holes accretion disks |
| title | The extremes of continuum and emission-line variability of AGN: Changing-look events and binary SMBHS |
| title_full | The extremes of continuum and emission-line variability of AGN: Changing-look events and binary SMBHS |
| title_fullStr | The extremes of continuum and emission-line variability of AGN: Changing-look events and binary SMBHS |
| title_full_unstemmed | The extremes of continuum and emission-line variability of AGN: Changing-look events and binary SMBHS |
| title_short | The extremes of continuum and emission-line variability of AGN: Changing-look events and binary SMBHS |
| title_sort | extremes of continuum and emission line variability of agn changing look events and binary smbhs |
| topic | galaxies: nuclei galaxies: seyfert quasars: emission lines quasars: supermassive binary black holes accretion disks |
| url | https://doiserbia.nb.rs/img/doi/1450-698X/2024/1450-698X2409001K.pdf |
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