EPISODIC ACTIVITIES OF SUPERMASSIVE BLACK HOLES AT REDSHIFT z <= 2: DRIVEN BY MERGERS?

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	EPISODIC ACTIVITIES OF SUPERMASSIVE BLACK HOLES AT REDSHIFT z <= 2: DRIVEN BY MERGERS?
	Li YR(李彦荣); Wang JM(王建民); Hu C(胡晨); Zhang S(张澍); Li, YR; Wang, JM; Yuan, YF; Hu, C; Zhang, S
刊名	ASTROPHYSICAL JOURNAL
	2010
卷号	710 期号:1 页码:878-885
关键词	galaxies: evolution galaxies: high-redshift quasars: general
通讯作者	[Li, Yan-Rong ; Wang, Jian-Min ; Hu, Chen ; Zhang, Shu] Chinese Acad Sci, Inst High Energy Phys, Key Lab Particle Astrophys, Beijing 100049, Peoples R China ; [Yuan, Ye-Fei] Univ Sci & Technol China, Ctr Astrophys, Hefei 230026, Peoples R China ; [Li, Yan-Rong] Chinese Acad Sci, Grad Univ, Beijing 100049, Peoples R China ; [Wang, Jian-Min] Chinese Acad Sci, Theoret Phys Ctr Sci Facil, Beijing 100864, Peoples R China
英文摘要	It has been suggested for quite a long time that galaxy mergers trigger activities of supermassive black holes (SMBHs) on the grounds of imaging observations of individual galaxies. To quantitatively examine this hypothesis, we calculate quasar luminosity functions (LFs) by manipulating the observed galaxy LFs (z less than or similar to 2) and theoretical merger rates from semi-analytical formulations. We find that the model reproduces the observed quasar LFs provided that the mass ratio (q) of the secondary galaxy to the newly formed one changes with cosmic time. The results show that the fraction of major mergers decreases from f(maj) similar to 0.2 at z similar to 2 to f(maj) -> 0 at z similar to 0. As a consequence, the newly formed SMBHs from major mergers at z similar to 2 may acquire a maximal spin due to the orbital angular momentum of the merging holes. Subsequently, random accretion led by minor mergers rapidly drives the SMBHs to spin down. Such an evolutionary trend of the SMBH spins is consistent with the fact that radiative efficiency of accreting SMBHs strongly declines with cosmic time, reported by Wang et al. This suggests that minor mergers are important in triggering activities of SMBHs at low redshift, while major mergers may dominate at high redshift.
学科主题	Astronomy & Astrophysics
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
原文出处	SCI
语种	英语
WOS记录号	WOS:000273850800070
内容类型	期刊论文
源URL	[http://ir.ihep.ac.cn/handle/311005/238665]
专题	高能物理研究所_粒子天体物理中心
作者单位	中国科学院高能物理研究所
推荐引用方式 GB/T 7714	Li YR,Wang JM,Hu C,et al. EPISODIC ACTIVITIES OF SUPERMASSIVE BLACK HOLES AT REDSHIFT z <= 2: DRIVEN BY MERGERS?[J]. ASTROPHYSICAL JOURNAL,2010,710(1):878-885.
APA	李彦荣.,王建民.,胡晨.,张澍.,Li, YR.,...&Zhang, S.(2010).EPISODIC ACTIVITIES OF SUPERMASSIVE BLACK HOLES AT REDSHIFT z <= 2: DRIVEN BY MERGERS?.ASTROPHYSICAL JOURNAL,710(1),878-885.
MLA	李彦荣,et al."EPISODIC ACTIVITIES OF SUPERMASSIVE BLACK HOLES AT REDSHIFT z <= 2: DRIVEN BY MERGERS?".ASTROPHYSICAL JOURNAL 710.1(2010):878-885.