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

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	Zhang, TJ; Liu, JR; Feng, LL; He, P; Fang, LZ; Zhang, TJ , Beijing Normal Univ, Dept Astron, Beijing 100875, Peoples R China
	X-ray emission of baryonic gas in the universe: Luminosity-temperature relationship and soft-band background
发表期刊	ASTROPHYSICAL JOURNAL
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
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.
	2006
ISSN	0004-637X
卷号	642 期号:2 页码:625-635
学科领域	Physics
收录类别	SCI
引用统计
文献类型	期刊论文
条目标识符	http://ir.itp.ac.cn/handle/311006/5987
专题	理论物理所科研产出_SCI论文
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.

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