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Centrally Concentrated X-Ray Radiation from an Extended Accreting Corona in Active Galactic Nuclei
Liu, B. F.1,2; Taam, Ronald E.3,4; Qiao, Erlin1,2; Yuan, Weimin1,2
2017-10-01
Source PublicationASTROPHYSICAL JOURNAL
Volume847Issue:2
AbstractThe X-ray emission from bright active galactic nuclei (AGNs) is believed to originate in a hot corona lying above a cold, geometrically thin accretion disk. A highly concentrated corona located within similar to 10 gravitational radii above the black hole is inferred from observations. Based on the accretion of interstellar medium/wind, a disk corona model has been proposed in which the corona is well coupled to the disk by radiation, thermal conduction, as well as by mass exchange. Such a model avoids artificial energy input to the corona and has been used to interpret the spectral features observed in AGN. In this work, it is shown that the bulk emission size of the corona is very small for the extended accretion flow in our model. More than 80% of the hard X-ray power is emitted from a small region confined within 10 Schwarzschild radii around a non-spinning black hole, which is expected to be even smaller accordingly for a spinning black hole. Here, the corona emission is more extended at higher Eddington ratios. The compactness parameter of the corona, l = L sigma(T)/R m(e)c(3), is shown to be in the range of 1-33 for Eddington ratios of 0.02-0.1. Combined with the electron temperature in the corona, this indicates that electron-positron pair production is not dominant in this regime. A positive relation between the compactness parameter and photon index is also predicted. By comparing the above model predictions with observational features, we find that the model is in agreement with observations.
SubtypeArticle
KeywordBlack Hole Physics Accretion Galaxies: Active Accretion Disks Galaxies: Nuclei X-rays: Galaxies
WOS HeadingsScience & Technology ; Physical Sciences
Funding OrganizationNational Program on Key Research and Development Project(2016YFA0400804) ; National Program on Key Research and Development Project(2016YFA0400804) ; National Natural Science Foundation of China(11673026) ; National Natural Science Foundation of China(11673026) ; Theoretical Institute for Advanced Research in Astrophysics in the Academia Sinica Institute of Astronomy Astrophysics ; Theoretical Institute for Advanced Research in Astrophysics in the Academia Sinica Institute of Astronomy Astrophysics ; National Program on Key Research and Development Project(2016YFA0400804) ; National Program on Key Research and Development Project(2016YFA0400804) ; National Natural Science Foundation of China(11673026) ; National Natural Science Foundation of China(11673026) ; Theoretical Institute for Advanced Research in Astrophysics in the Academia Sinica Institute of Astronomy Astrophysics ; Theoretical Institute for Advanced Research in Astrophysics in the Academia Sinica Institute of Astronomy Astrophysics
DOI10.3847/1538-4357/aa894c
WOS KeywordADVECTION-DOMINATED ACCRETION ; QUASAR PG 1115+080 ; BLACK-HOLES ; SEYFERT-GALAXIES ; IRON K ; EMITTING REGION ; 1H 0707-495 ; TIME LAGS ; THIN DISK ; NGC 4151
Indexed BySCI
Language英语
Funding OrganizationNational Program on Key Research and Development Project(2016YFA0400804) ; National Program on Key Research and Development Project(2016YFA0400804) ; National Natural Science Foundation of China(11673026) ; National Natural Science Foundation of China(11673026) ; Theoretical Institute for Advanced Research in Astrophysics in the Academia Sinica Institute of Astronomy Astrophysics ; Theoretical Institute for Advanced Research in Astrophysics in the Academia Sinica Institute of Astronomy Astrophysics ; National Program on Key Research and Development Project(2016YFA0400804) ; National Program on Key Research and Development Project(2016YFA0400804) ; National Natural Science Foundation of China(11673026) ; National Natural Science Foundation of China(11673026) ; Theoretical Institute for Advanced Research in Astrophysics in the Academia Sinica Institute of Astronomy Astrophysics ; Theoretical Institute for Advanced Research in Astrophysics in the Academia Sinica Institute of Astronomy Astrophysics
WOS Research AreaAstronomy & Astrophysics
WOS SubjectAstronomy & Astrophysics
WOS IDWOS:000411792200004
Citation statistics
Cited Times:3[WOS]   [WOS Record]     [Related Records in WOS]
Document Type期刊论文
Identifierhttp://ir.bao.ac.cn/handle/114a11/20117
Collection空间科学研究部
Affiliation1.Chinese Acad Sci, Key Lab Space Astron & Technol, Natl Astron Observ, Beijing 100012, Peoples R China
2.Univ Chinese Acad Sci, Sch Astron & Space Sci, 19A Yuquan Rd, Beijing 100049, Peoples R China
3.Acad Sinica, Inst Astron & Astrophys, TIARA, POB 23-141, Taipei 10617, Taiwan
4.Northwestern Univ, Dept Phys & Astron, 2131 Tech Dr, Evanston, IL 60208 USA
Recommended Citation
GB/T 7714
Liu, B. F.,Taam, Ronald E.,Qiao, Erlin,et al. Centrally Concentrated X-Ray Radiation from an Extended Accreting Corona in Active Galactic Nuclei[J]. ASTROPHYSICAL JOURNAL,2017,847(2).
APA Liu, B. F.,Taam, Ronald E.,Qiao, Erlin,&Yuan, Weimin.(2017).Centrally Concentrated X-Ray Radiation from an Extended Accreting Corona in Active Galactic Nuclei.ASTROPHYSICAL JOURNAL,847(2).
MLA Liu, B. F.,et al."Centrally Concentrated X-Ray Radiation from an Extended Accreting Corona in Active Galactic Nuclei".ASTROPHYSICAL JOURNAL 847.2(2017).
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