The advection-dominated accretion flow plus thin accretion disk model for two low-luminosity active galactic nuclei: M81 and NGC 4579
文献类型：期刊论文
| 作者 | Xu, Ya-Di1; Cao, Xin-Wu2 |
| 刊名 | RESEARCH IN ASTRONOMY AND ASTROPHYSICS
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| 出版日期 | 2009-04-01 |
| 卷号 | 9期号:4页码:401-408 |
| 关键词 | accretion black hole physics galaxies:active radiation mechanisms: thermal galaxies: individual (M81 accretion disks NGC 4579) |
| 英文摘要 | It was found that advection-dominated accretion flow (ADAF)+thin disk model calculations can reproduce the observed spectral energy distributions (SEDs) of two low-luminosity active galactic nuclei (AGNs), provided they are accreting at similar to 0.01 - 0.03 Eddington rates and the thin disks are truncated to ADAFs at similar to 100R(S) (R(S) is the Schwarzschild radius) for M81 and NGC 4579 (Quataert et al. 1999). However, the black hole masses adopted in their work are about one order of magnitude lower than recent measurements on these two sources. Adopting the well estimated black hole masses, our ADAF+thin disk model calculations can reproduce the observed SEDs of these two low-luminosity AGNs, if the black hole is accreting at 2.5 x 10(-4) Eddington rates with the thin disk truncated at R(tr) = 120R(S) for M81 ((m) over dot = 3.3 x 10(-3) and R(tr) = 80R(S) are required for NGC 4579). The transition zones with temperature from the thin disk with similar to 10(4) - 10(5) to similar to 10(9) - 10(10) K in the ADAF will inevitably emit thermal X-ray lines, which provides a useful diagnosis of their physical properties. The observed widths of the thermal X-ray iron lines at similar or equal to 6.8 keV are consistent with Doppler broadening by Keplerian motion of the gases in the transition zones at similar to 100RS. We use the structure of the transition zone between the ADAF and the thin disk derived by assuming the turbulent diffusive heat mechanism to calculate their thermal X-ray line emission with the standard software package Astrophysical Plasma Emission Code (APEC). Comparing them with the equivalent widths of the observed thermal X-ray iron lines in these two sources, we find that the turbulent diffusive heat mechanism seems to be unable to reproduce the observed thermal X-ray line emission. The test of the evaporation model for the accretion mode transition with the observed thermal X-ray line emission is briefly discussed. |
| WOS标题词 | Science & Technology ; Physical Sciences |
| 类目[WOS] | Astronomy & Astrophysics |
| 研究领域[WOS] | Astronomy & Astrophysics |
| 关键词[WOS] | X-RAY BINARIES ; BLACK-HOLE ; EMISSION-LINE ; SAGITTARIUS-A ; DWARF NOVAE ; EVAPORATION ; QUIESCENCE ; TRANSITION ; GALAXIES ; NGC-4579 |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS记录号 | WOS:000265485000003 |
| 源URL | [http://119.78.226.72/handle/331011/19548]  |
| 专题 | 上海天文台_星系宇宙学重点实验室 |
| 作者单位 | 1.Shanghai Jiao Tong Univ, Dept Phys, Shanghai 200240, Peoples R China 2.Chinese Acad Sci, Shanghai Astron Observ, Shanghai 200030, Peoples R China |
| 推荐引用方式 GB/T 7714 | Xu, Ya-Di,Cao, Xin-Wu. The advection-dominated accretion flow plus thin accretion disk model for two low-luminosity active galactic nuclei: M81 and NGC 4579[J]. RESEARCH IN ASTRONOMY AND ASTROPHYSICS,2009,9(4):401-408. |
| APA | Xu, Ya-Di,&Cao, Xin-Wu.(2009).The advection-dominated accretion flow plus thin accretion disk model for two low-luminosity active galactic nuclei: M81 and NGC 4579.RESEARCH IN ASTRONOMY AND ASTROPHYSICS,9(4),401-408. |
| MLA | Xu, Ya-Di,et al."The advection-dominated accretion flow plus thin accretion disk model for two low-luminosity active galactic nuclei: M81 and NGC 4579".RESEARCH IN ASTRONOMY AND ASTROPHYSICS 9.4(2009):401-408. |
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来源：上海天文台
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