Are 'Changing-Look' Active Galactic Nuclei Special in the Coevolution of Supermassive Black Holes and their Hosts? I
| Autor: | Wang, J., Zheng, W. K., Brink, T. G., Xu, D. W., Filippenko, A. V., Gao, C., Xie, C. H., Wei, J. Y. |
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| Rok vydání: | 2023 |
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| Druh dokumentu: | Working Paper |
| Popis: | The nature of the so-called ``changing-look'' (CL) active galactic nucleus (AGN), which is characterized by spectral-type transitions within $\sim10$~yr, remains an open question. As the first in our series of studies, we here attempt to understand the CL phenomenon from a view of the coevolution of AGNs and their host galaxies (i.e., if CL-AGNs are at a specific evolutionary stage) by focusing on the SDSS local ``partially obscured'' AGNs in which the stellar population of the host galaxy can be easily measured in the integrated spectra. A spectroscopic follow-up program using the Xinglong 2.16~m, Lick/Shane 3~m, and Keck 10~m telescopes enables us to identify in total 9 CL-AGNs from a sample of 59 candidates selected by their mid-infrared variability. Detailed analysis of these spectra shows that the host galaxies of the CL-AGNs are biased against young stellar populations and tend to be dominated by intermediate-age stellar populations. This motivates us to propose that CL-AGNs are probably particular AGNs at a specific evolutionary stage, such as a transition stage from ``feast'' to ``famine'' fueling of the supermassive black hole. In addition, we reinforce the previous claim that CL-AGNs tend to be biased against both a high Eddington ratio and a high bolometric luminosity, suggesting that the disk-wind broad-line-region model is a plausible explanation of the CL phenomenon. Comment: Replaced by updated Acknowledgments. arXiv admin note: substantial text overlap with arXiv:2210.03928 |
| Databáze: | arXiv |
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