X-ray emission of baryonic gas in the universe: Luminosity-temperature relationship and soft-band background

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	X-ray emission of baryonic gas in the universe: Luminosity-temperature relationship and soft-band background
	Zhang, TJ; Liu, JR; Feng, LL; He, P; Fang, LZ; Zhang, TJ , Beijing Normal Univ, Dept Astron, Beijing 100875, Peoples R China
刊名	ASTROPHYSICAL JOURNAL
	2006
卷号	642 期号:2 页码:625-635
关键词	Ly-alpha Forest Essentially Nonoscillatory Schemes Large-scale Structure Intergalactic Medium Transmitted Flux Intracluster Medium Power Spectrum Cosmological Simulations Burgers Turbulence Galaxy Clusters
ISSN号	0004-637X
英文摘要	We study the X-ray emission of baryon fluid in the universe using the WIGEON cosmological hydrodynamic simulations. It has been revealed that cosmic baryon fluid in the nonlinear regime behaves like Burgers turbulence, i.e., the fluid field consists of shocks. Like turbulence in incompressible fluid, the Burgers turbulence plays an important role in converting the kinetic energy of the fluid to thermal energy and heats the gas. We show that the simulation sample of the Lambda CDMmodel without adding extra heating sources can fit well the observed distributions of X-ray luminosity versus temperature (L-X vs. T) of galaxy groups and is also consistent with the distributions of X-ray luminosity versus velocity dispersion (L-X vs. sigma). Because the baryonic gas is multiphase, the L-X-T and L-X-sigma distributions are significantly scattered. If we describe the relationships by power laws L-X alpha T-alpha LT and L-X alpha sigma(alpha LV), we find alpha(LT) > 2: 5 and alpha(LV) > 2:1. The X-ray background in the soft 0.5-2 keV band emitted by the baryonic gas in the temperature range 10(5) < T < 10(7) K has also been calculated. We show that of the total background, ( 1) no more than 2% comes from the region with temperature less than 10(6.5) K, and ( 2) no more than 7% is from the region of dark matter with mass density rho dm < 50 (rho) over bar (dm). The region of rho dm > 50 (rho) over bar (dm) is generally clustered and discretely distributed. Therefore, almost all of the soft X-ray background comes from clustered sources, and the contribution from truly diffuse gas is probably negligible. This point agrees with current X-ray observations.
学科主题	Physics
URL标识	查看原文
WOS记录号	WOS:000237554200002
公开日期	2012-08-02
内容类型	期刊论文
源URL	[http://ir.itp.ac.cn/handle/311006/5987]
专题	理论物理研究所_理论物理所1978-2010年知识产出
通讯作者	Zhang, TJ , Beijing Normal Univ, Dept Astron, Beijing 100875, Peoples R China
推荐引用方式 GB/T 7714	Zhang, TJ,Liu, JR,Feng, LL,et al. X-ray emission of baryonic gas in the universe: Luminosity-temperature relationship and soft-band background[J]. ASTROPHYSICAL JOURNAL,2006,642(2):625-635.
APA	Zhang, TJ,Liu, JR,Feng, LL,He, P,Fang, LZ,&Zhang, TJ , Beijing Normal Univ, Dept Astron, Beijing 100875, Peoples R China.(2006).X-ray emission of baryonic gas in the universe: Luminosity-temperature relationship and soft-band background.ASTROPHYSICAL JOURNAL,642(2),625-635.
MLA	Zhang, TJ,et al."X-ray emission of baryonic gas in the universe: Luminosity-temperature relationship and soft-band background".ASTROPHYSICAL JOURNAL 642.2(2006):625-635.