Discovery of high-amplitude X-ray variability in the Seyfert-LINER transition galaxy NGC 7589
文献类型：期刊论文
| 作者 | Yuan, W ; Komossa, S; Xu, D; Osborne, JP; Watson, MG; McMahon, RG
|
| 刊名 | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
 |
| 出版日期 | 2004-09-21 |
| 卷号 | 353期号:3页码:L29-L33 |
| 关键词 | galaxies : active galaxies : individual : NGC 7589 X-ray : galaxies |
| 英文摘要 | We present the first result of a programme to search for large flux variations in the X-ray sources of the XMM Serendipitous Survey compared to previous ROSAT observations. An increase in X-ray flux by a factor >10 was discovered from the nucleus of the galaxy NGC7589 on a time-scale of less than 5 yr. The 0.4-10 keV XMM spectrum can be approximated by a power law with photon index of 1.7-1.8, though it seems to flatten above 5 keV, suggesting a possible complex model, such as partial covering or disc reflection. A classification based on an analysis of its optical spectrum places NGC 7589 in the Seyfert region, but close to the Seyfert-LINER (low-ionization nuclear emission-line region) borderline on the active galactic nucleus (AGN) diagnostic diagrams. We classify NGC 7589 as either Seyfert 1.9 or LINER I, in the light of the detection of a broad Halpha line, which makes NGC 7589 an AGN in the low-luminosity regime. We interpret the observed variability in terms of either changes in covering factor of absorbing gas in the AGN, or variability in the intrinsic X-ray luminosity. Should the latter be the case, the inferred Eddington accretion rate increased from the radiatively inefficient accretion-dominated regime to a value close to the putative critical value, at which a transition of the accretion mode is supposed to take place. This possibility presents a new prospect of studying accretion physics in the central black holes of external galaxies by direct observing changes of 'spectral state', as is common in stellar black hole binary systems. |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS记录号 | WOS:000224300700002 |
| 源URL | [http://ir.bao.ac.cn/handle/114a11/6955]  |
| 专题 | 国家天文台_空间科学研究部 |
| 作者单位 | 1.Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England 2.Max Planck Inst Extraterr Phys, D-85741 Garching, Germany 3.Chinese Acad Sci, Natl Astron Observ, Beijing 100012, Peoples R China 4.Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England |
| 推荐引用方式 GB/T 7714 | Yuan, W,Komossa, S,Xu, D,et al. Discovery of high-amplitude X-ray variability in the Seyfert-LINER transition galaxy NGC 7589[J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,2004,353(3):L29-L33. |
| APA | Yuan, W,Komossa, S,Xu, D,Osborne, JP,Watson, MG,&McMahon, RG.(2004).Discovery of high-amplitude X-ray variability in the Seyfert-LINER transition galaxy NGC 7589.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,353(3),L29-L33. |
| MLA | Yuan, W,et al."Discovery of high-amplitude X-ray variability in the Seyfert-LINER transition galaxy NGC 7589".MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 353.3(2004):L29-L33. |
入库方式： OAI收割
来源：国家天文台
浏览0
下载0
收藏0
其他版本
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。