Understanding the AGN-host connection in partially obscured active galactic nuclei. I. The nature of AGN plus HII composites
文献类型：期刊论文
| 作者 | Wang, J.; Wei, J. Y. |
| 刊名 | ASTROPHYSICAL JOURNAL
 |
| 出版日期 | 2008-05-20 |
| 卷号 | 679期号:1页码:86-100 |
| 关键词 | galaxies : active galaxies : evolution galaxies : nuclei |
| 英文摘要 | The goal of our serial papers is to examine the evolutionary connection between an active galactic nucleus (AGN) and star formation in the AGN's host galaxy for partially obscured AGNs (i.e., Seyfert 1.8 and 1.9 galaxies). Taking advantage of these galaxies, the properties of both components can be studied together by direct measurements. In this paper, we focus on broad-line composite galaxies (composite AGNs), which are located between the theoretical and empirical separation lines in the [N II]/H alpha versus [O III]/H beta diagram. These galaxies are selected from the composite galaxies provided by the SDSS DR4 MPA/JHU catalogs. After we reanalyze the spectra, we perform a fine classification for the 85 composite AGNs in terms of Baldwin-Phillips-Terlevich (BPT) diagrams. All objects located below the three theoretical separation lines are associated with a young stellar population (< 1Gyr), while either a young or old stellar population is identified in the individual multiply classified objects. The multiply classified objects with very old stellar populations are located in the LINER region in the [O I]/H alpha versus [O III]/H beta diagram. We then consider the connection between AGNs and star formation to derive the key results. The Eddington ratio inferred from the broad H alpha emission, the age of the stellar population of the AGN's host as assessed by D-n(4000), and the line ratio [O I]/H alpha are found to be related to each other. These relations strongly support an evolutionary scenario in which AGNs evolve from a high L/L-Edd state with a soft spectrum to a low L/L-Edd state with a hard spectrum as the young stellar population ages and fades. The significant correlation between the line ratio [O I]/H alpha and D-n(4000) leads us to suggest that the line ratio could be used to trace the age of the stellar population in type I AGNs. |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS记录号 | WOS:000255818600009 |
| 源URL | [http://ir.bao.ac.cn/handle/114a11/7431]  |
| 专题 | 国家天文台_空间科学研究部 |
| 作者单位 | Chinese Acad Sci, Natl Astron Observ, Beijing 100012, Peoples R China |
| 推荐引用方式 GB/T 7714 | Wang, J.,Wei, J. Y.. Understanding the AGN-host connection in partially obscured active galactic nuclei. I. The nature of AGN plus HII composites[J]. ASTROPHYSICAL JOURNAL,2008,679(1):86-100. |
| APA | Wang, J.,&Wei, J. Y..(2008).Understanding the AGN-host connection in partially obscured active galactic nuclei. I. The nature of AGN plus HII composites.ASTROPHYSICAL JOURNAL,679(1),86-100. |
| MLA | Wang, J.,et al."Understanding the AGN-host connection in partially obscured active galactic nuclei. I. The nature of AGN plus HII composites".ASTROPHYSICAL JOURNAL 679.1(2008):86-100. |
入库方式： OAI收割
来源：国家天文台
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