Metallicity and H I Column Density Properties of Damped Lyα Systems

	Metallicity and H I Column Density Properties of Damped Lyα Systems
	Hou, JL ; Shu, CG ; Shen, SY ; Chang, RX ; Chen, WP ; Fu, CQ
刊名	ASTROPHYSICAL JOURNAL
	2005-05-10
卷号	624 期号:2 页码:561-570
关键词	galaxies : evolution galaxies : formation quasars : absorption lines
英文摘要	On the basis of the disk galaxy formation theory within the framework of the standard &ULambda; CDM hierarchical picture (Mo, Mao,& White), we selected modeled damped Lyα systems (DLAs), according to their observational criterion N-H (I) &GSIM; 10(20.3) cm(-2) by Monte Carlo simulation using random inclinations to examine their observed properties. By best-fitting the predicted metallicity distribution to the observed ones, we get an effective yield of about 0.25 Z(&ODOT;) for DLAs, which is comparable to those for the SMC and LMC. And the predicted distribution is the same as that of the observations at a significance level of higher than 60%. The predicted column density distribution of modeled DLAs is compared with the observed ones with the corresponding number density, with a discussion of the gas content. We found that the predicted number density n(z) at redshift 3 agrees well with the observed value, but the gas content &UOmega;(DLA) is about 3 times larger than that observed, since our model predicts more DLAs with higher column density. It should be noted that the predicted star formation rate density contributed by DLAs is consistent with the most recent observations if the star formation timescale in DLAs is assumed to be 1-3 Gyr. Meanwhile, the connection between DLAs and Lyman break galaxies (LBGs) is discussed by comparing their UV luminosity functions, which shows that the DLAs' host galaxies are much fainter than LBGs. We also predict that only a few percent of DLAs can host LBGs, which is also consistent with current observations. However, there is a discrepancy between model prediction and observation in the correlation between metallicity and H I column density for DLAs. We suggest that this could result from either the inadequacy of a Schmidt-type star formation law at high redshift, the diversities of DLA populations, or the model limitations. Although our current simple model cannot fully reproduce the observed DLA velocity distribution, we argue that this kind of model can still provide valuable information about the nature of DLAs.
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	HIGH-REDSHIFT GALAXIES ; LYMAN-BREAK GALAXIES ; CHEMO-SPECTROPHOTOMETRIC EVOLUTION ; STAR-FORMATION HISTORY ; CHEMICAL EVOLUTION ; SPIRAL GALAXIES ; FORMATION MODELS ; ABUNDANCE DATABASE ; MOLECULAR-HYDROGEN ; DEPLETION PATTERN
收录类别	SCI
语种	英语
WOS记录号	WOS:000228916000008
公开日期	2010-11-08
内容类型	期刊论文
源URL	[http://119.78.226.72//handle/331011/12004]
专题	上海天文台_星系宇宙学重点实验室
作者单位	1.CAS, Shanghai Astron Observ, Shanghai 200030, Peoples R China 2.Natl Cent Univ, Grad Inst Astron, Chungli 32054, Taiwan 3.Shanghai Normal Univ, Joint Ctr Astrophys, Shanghai 200234, Peoples R China
推荐引用方式 GB/T 7714	Hou, JL,Shu, CG,Shen, SY,et al. Metallicity and H I Column Density Properties of Damped Lyα Systems[J]. ASTROPHYSICAL JOURNAL,2005,624(2):561-570.
APA	Hou, JL,Shu, CG,Shen, SY,Chang, RX,Chen, WP,&Fu, CQ.(2005).Metallicity and H I Column Density Properties of Damped Lyα Systems.ASTROPHYSICAL JOURNAL,624(2),561-570.
MLA	Hou, JL,et al."Metallicity and H I Column Density Properties of Damped Lyα Systems".ASTROPHYSICAL JOURNAL 624.2(2005):561-570.