Galaxies Lighting Up: Discovery of Seventy New Turn-on Changing-look Active Galactic Nuclei
“Changing-look active galactic nuclei” (CL AGN) show dramatic, rapid changes in optical/UV continuum and broad-line emission. The majority of CL AGN have been found dimming as “turn-off” CL AGN because most selection methods start from samples of spectroscopically confirmed quasars. We present here...
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ad94ed |
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| author | Qian Yang Paul J. Green Xue-Bing Wu Michael Eracleous Linhua Jiang Yuming Fu |
| author_facet | Qian Yang Paul J. Green Xue-Bing Wu Michael Eracleous Linhua Jiang Yuming Fu |
| author_sort | Qian Yang |
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| description | “Changing-look active galactic nuclei” (CL AGN) show dramatic, rapid changes in optical/UV continuum and broad-line emission. The majority of CL AGN have been found dimming as “turn-off” CL AGN because most selection methods start from samples of spectroscopically confirmed quasars. We present here a sample of 82 spectroscopically confirmed “turn-on” CL AGN, 70 of which are newly identified. The turn-on CL AGN are selected from spectroscopically classified galaxies with subsequent significant and dramatic variability in both the optical and mid-infrared bands, indicating a mechanism of changing accretion rate of the supermassive black holes (BHs) rather than variable obscuration. Based on their bright state Eddington ratios, turn-on CL AGN are associated with lower accretion rates compared to turn-off CL AGN or typical Sloan Digital Sky Survey quasars with similar redshift and magnitude distributions, even though turn-on CL AGN have lower BH masses. Most turn-on CL AGN reside in host galaxies that follow local relations between the central BH mass and host galaxy properties, such as stellar mass and velocity dispersion. However, their host galaxies have higher mass than normal inactive galaxies, with star formation rates more similar to hosts of Type 2 AGN than to the overall galaxy population. |
| format | Article |
| id | doaj-art-30541976d8f84743a1a276458aafb956 |
| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj-art-30541976d8f84743a1a276458aafb9562025-02-05T17:24:15ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198019110.3847/1538-4357/ad94edGalaxies Lighting Up: Discovery of Seventy New Turn-on Changing-look Active Galactic NucleiQian Yang0https://orcid.org/0000-0002-6893-3742Paul J. Green1https://orcid.org/0000-0002-8179-9445Xue-Bing Wu2https://orcid.org/0000-0002-7350-6913Michael Eracleous3https://orcid.org/0000-0002-3719-940XLinhua Jiang4https://orcid.org/0000-0003-4176-6486Yuming Fu5https://orcid.org/0000-0002-0759-0504Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA ; qian.yang@cfa.harvard.eduCenter for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA ; qian.yang@cfa.harvard.eduDepartment of Astronomy, School of Physics, Peking University , Beijing 100871, People’s Republic of China; Kavli Institute for Astronomy and Astrophysics, Peking University , Beijing 100871, People’s Republic of ChinaDepartment of Astronomy and Astrophysics and Institute for Gravitation and the Cosmos, Penn State University , 525 Davey Lab, 251 Pollock Road, University Park, PA 16802, USAKavli Institute for Astronomy and Astrophysics, Peking University , Beijing 100871, People’s Republic of ChinaLeiden Observatory, Leiden University , P.O. Box 9513, NL-2300 RA Leiden, The Netherlands“Changing-look active galactic nuclei” (CL AGN) show dramatic, rapid changes in optical/UV continuum and broad-line emission. The majority of CL AGN have been found dimming as “turn-off” CL AGN because most selection methods start from samples of spectroscopically confirmed quasars. We present here a sample of 82 spectroscopically confirmed “turn-on” CL AGN, 70 of which are newly identified. The turn-on CL AGN are selected from spectroscopically classified galaxies with subsequent significant and dramatic variability in both the optical and mid-infrared bands, indicating a mechanism of changing accretion rate of the supermassive black holes (BHs) rather than variable obscuration. Based on their bright state Eddington ratios, turn-on CL AGN are associated with lower accretion rates compared to turn-off CL AGN or typical Sloan Digital Sky Survey quasars with similar redshift and magnitude distributions, even though turn-on CL AGN have lower BH masses. Most turn-on CL AGN reside in host galaxies that follow local relations between the central BH mass and host galaxy properties, such as stellar mass and velocity dispersion. However, their host galaxies have higher mass than normal inactive galaxies, with star formation rates more similar to hosts of Type 2 AGN than to the overall galaxy population.https://doi.org/10.3847/1538-4357/ad94edQuasarsActive galactic nucleiSupermassive black holesAGN host galaxies |
| spellingShingle | Qian Yang Paul J. Green Xue-Bing Wu Michael Eracleous Linhua Jiang Yuming Fu Galaxies Lighting Up: Discovery of Seventy New Turn-on Changing-look Active Galactic Nuclei The Astrophysical Journal Quasars Active galactic nuclei Supermassive black holes AGN host galaxies |
| title | Galaxies Lighting Up: Discovery of Seventy New Turn-on Changing-look Active Galactic Nuclei |
| title_full | Galaxies Lighting Up: Discovery of Seventy New Turn-on Changing-look Active Galactic Nuclei |
| title_fullStr | Galaxies Lighting Up: Discovery of Seventy New Turn-on Changing-look Active Galactic Nuclei |
| title_full_unstemmed | Galaxies Lighting Up: Discovery of Seventy New Turn-on Changing-look Active Galactic Nuclei |
| title_short | Galaxies Lighting Up: Discovery of Seventy New Turn-on Changing-look Active Galactic Nuclei |
| title_sort | galaxies lighting up discovery of seventy new turn on changing look active galactic nuclei |
| topic | Quasars Active galactic nuclei Supermassive black holes AGN host galaxies |
| url | https://doi.org/10.3847/1538-4357/ad94ed |
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