TOWARD PRECISE CONSTRAINTS ON THE GROWTH OF MASSIVE BLACK HOLES

	TOWARD PRECISE CONSTRAINTS ON THE GROWTH OF MASSIVE BLACK HOLES
	Yu, Qingjuan 1,2,3; Lu, Youjun1,2,3,4
刊名	ASTROPHYSICAL JOURNAL
	2008-12-20
卷号	689 期号:2 页码:732-754
关键词	black hole physics cosmology: miscellaneous galaxies: active galaxies: evolution galaxies: nuclei quasars: general
英文摘要	Growth of massive black holes (MBHs) in galactic centers comes mainly from gas accretion during their QSO/AGN phases. In this paper we apply an extended Soltan argument, connecting the local MBH mass function with the time integral of the QSO luminosity function to the demography of MBHs and QSOs from recent optical and X-ray surveys, and obtain robust constraints on the luminosity evolution ( or mass growth history) of individual QSOs ( or MBHs). We find that the luminosity evolution probably involves two phases, an initial exponentially increasing phase set by the Eddington limit and a following phase in which the luminosity declines with time as a power law (with a slope of similar to -1.2 to -1.3) set by a self-similar long-term evolution of disk accretion. Neither an evolution involving only the increasing phase with a single Eddington ratio nor an exponentially declining pattern in the second phase is likely. The period of a QSO radiating at a luminosity higher than 10% of its peak value is about (2-3) x 10(8) yr, during which the MBH obtains similar to 80% of its mass. The mass-to-energy conversion efficiency is similar or equal to 0.16 +/- 0.04(-0)(+0.05), with the latter error accounting for the maximum uncertainty due to Compton-thick AGNs. The expected Eddington ratios in QSOs from the constrained luminosity evolution cluster around a single value close to 0.5-1 for high-luminosity QSOs and extend to a wide range of lower values for low-luminosity ones. The Eddington ratios for high-luminosity QSOs appear to conflict with those estimated from observations (similar to 0.25) by using some virial mass estimators for MBHs in QSOs, unless the estimators systematically overestimate MBH masses by a factor of 2-4. We also infer the fraction of optically obscured QSOs, similar to 60% -80%. The constraints obtained above are not affected significantly by MBH mergers and multiple times of nuclear activity ( e. g., triggered by multiple times of galaxy wet major mergers) in the MBH growth history. We discuss further applications of the luminosity evolution of individual QSOs to obtaining the MBH mass function at high redshifts and the cosmic evolution of triggering rates of nuclear activity.
收录类别	SCI
语种	英语
WOS记录号	WOS:000261189600007
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/7408]
专题	国家天文台_星系宇宙学研究部
作者单位	1.Univ Toronto, Canadian Inst Theoret Astrophys, Toronto, ON M5S 3H8, Canada 2.Univ Toronto, Dept Astron & Astrophys, Toronto, ON M5S 3H8, Canada 3.Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA 4.Chinese Acad Sci, Natl Astron Observ, Beijing 100012, Peoples R China
推荐引用方式 GB/T 7714	Yu, Qingjuan,Lu, Youjun. TOWARD PRECISE CONSTRAINTS ON THE GROWTH OF MASSIVE BLACK HOLES[J]. ASTROPHYSICAL JOURNAL,2008,689(2):732-754.
APA	Yu, Qingjuan,&Lu, Youjun.(2008).TOWARD PRECISE CONSTRAINTS ON THE GROWTH OF MASSIVE BLACK HOLES.ASTROPHYSICAL JOURNAL,689(2),732-754.
MLA	Yu, Qingjuan,et al."TOWARD PRECISE CONSTRAINTS ON THE GROWTH OF MASSIVE BLACK HOLES".ASTROPHYSICAL JOURNAL 689.2(2008):732-754.