THE DISK EVAPORATION MODEL FOR THE SPECTRAL FEATURES OF LOW-LUMINOSITY ACTIVE GALACTIC NUCLEI

	THE DISK EVAPORATION MODEL FOR THE SPECTRAL FEATURES OF LOW-LUMINOSITY ACTIVE GALACTIC NUCLEI
	Qiao, EL1 ; Liu, BF1 ; Panessa, F 2; Liu JY(刘杰英)3,4
刊名	ASTROPHYSICAL JOURNAL
	2013-11-10
卷号	777 期号:2
关键词	accretion, accretion disks black hole physics galaxies: active X-rays: galaxies
ISSN号	0004-637X
通讯作者	Qiao, E (reprint author), Chinese Acad Sci, Natl Astron Observ, Beijing 100012, Peoples R China.
产权排序	第三完成单位
英文摘要	Observations show that the accretion flows in low-luminosity active galactic nuclei probably have a two-component structure with an inner, hot, optically thin, advection-dominated accretion flow (ADAF) and an outer, truncated, cool, optically thick accretion disk. As shown by Taam et al., the truncation radius as a function of mass accretion rate is strongly affected by including the magnetic field within the framework of disk evaporation model, i.e., an increase in the magnetic field results in a smaller truncation radius of the accretion disk. In this work, we calculate the emergent spectrum of an inner ADAF + an outer truncated accretion disk around a supermassive black hole based on the prediction by Taam et al.. It is found that an increase in the magnetic field from beta = 0.8 to beta = 0.5 (with magnetic pressure p(m) = B-2/8 pi = (1 - beta)p(tot), p(tot) = p(gas) + p(m)) results in a factor of similar to 8.7 increase in the luminosity from the truncated accretion disk. Meanwhile, results of the peak emission of the truncated accretion disk shift toward a a factor of similar to 5 higher frequency. We found that the equipartition of gas pressure to magnetic pressure, i.e., beta = 0.5, failed to explain the observed anti-correlation between (L2-10) (keV)/L-Edd and the bolometric correction kappa(2-10 keV) (with kappa(2-10 keV) = L-bol/L2-10 keV). The emergent spectra for larger values of beta = 0.8 or beta = 0.95 can explain the observed L2-10 keV/L-Edd-kappa(2-10 keV) correlation. We argue that in the disk evaporation model, the electrons in the corona are assumed to be heated only by a transfer of energy from the ions to electrons via Coulomb collisions, which is reasonable for accretion with a lower mass accretion rate. Coulomb heating is the dominated heating mechanism for the electrons only if the magnetic field is strongly sub-equipartition, which is roughly consistent with observations.
学科主题	Astronomy & Astrophysics
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	ADVECTION-DOMINATED ACCRETION ; RADIATIVELY INEFFICIENT ACCRETION ; X-RAY BINARIES ; BLACK-HOLE BINARIES ; BIG BLUE BUMP ; ENERGY-DISTRIBUTIONS ; EDDINGTON RATIO ; NUMERICAL-SIMULATION ; EFFICIENCY ACCRETION ; SEYFERT-GALAXIES
收录类别	SCI
原文出处	http://iopscience.iop.org/article/10.1088/0004-637X/777/2/102/meta
语种	英语
WOS记录号	WOS:000326218800021
内容类型	期刊论文
源URL	[http://ir.ynao.ac.cn/handle/114a53/5229]
专题	云南天文台_恒星物理研究组云南天文台_中国科学院天体结构与演化重点实验室
作者单位	1.National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China 2.INAF-Istituto di Astrofisica e Planetologia Spaziali di Roma (IAPS), Via del Fosso del Cavaliere 100, I-00133 Roma, Italy 3.Yunnan Observatories, Chinese Academy of Sciences, P.O. Box 110, Kunming 650011, China 4.Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, Kunming 650011, China
推荐引用方式 GB/T 7714	Qiao, EL,Liu, BF,Panessa, F,et al. THE DISK EVAPORATION MODEL FOR THE SPECTRAL FEATURES OF LOW-LUMINOSITY ACTIVE GALACTIC NUCLEI[J]. ASTROPHYSICAL JOURNAL,2013,777(2).
APA	Qiao, EL,Liu, BF,Panessa, F,&Liu JY.(2013).THE DISK EVAPORATION MODEL FOR THE SPECTRAL FEATURES OF LOW-LUMINOSITY ACTIVE GALACTIC NUCLEI.ASTROPHYSICAL JOURNAL,777(2).
MLA	Qiao, EL,et al."THE DISK EVAPORATION MODEL FOR THE SPECTRAL FEATURES OF LOW-LUMINOSITY ACTIVE GALACTIC NUCLEI".ASTROPHYSICAL JOURNAL 777.2(2013).