Entropy of gas and dark matter in galaxy clusters

	Entropy of gas and dark matter in galaxy clusters
	Faltenbacher, Andreas ; Hoffman, Yehuda ; Gottloeber, Stefan ; Yepes, Gustavo
刊名	MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
	2007-04-11
卷号	376 期号:3 页码:1327-1334
关键词	methods : numerical galaxies : clusters : general
英文摘要	On the basis of a large-scale 'adiabatic', namely non-radiative and non-dissipative, cosmological smooth particle hydrodynamic simulation we compare the entropy profiles of the gas and the dark matter (DM) in galaxy clusters. We employ the quantity K-g = 3k(B)T(g)rho(-2/3)(g)/(mu m(p)) = sigma(2)(g)rho(-2/3)(g) as measure for the entropy of the intracluster gas. By analogy the DM entropy is defined as K-DM = sigma(2)(DM)rho(-2/3)(DM)(sigma(2)(DM) is the 3D velocity dispersion of the DM). The DM entropy is related to the DM phase-space density by K-DM proportional to Q(DM)(-2/3). In accord with other studies, the radial DM phase-space density profile follows a power-law behaviour, Q(DM) proportional to r(-1.82), which corresponds to K-DM proportional to r(1.21). The simulated intracluster gas has a flat entropy core within (0.8 +/- 0.4)R-s, where R-s is the Navarro-Frenk-White scale radius. The outer profile follows the DM behaviour, K-g proportional to r(1.21), in close agreement with X-ray observations. Upon scaling the DM and gas densities by their mean cosmological values, we find that outside the entropy core a constant ratio of K-g/K-DM = 0.71 +/- 0.18 prevails. By extending the definition of the gas temperature to include also the bulk kinetic energy the ratio of the DM and gas extended entropy is found to be unity for r greater than or similar to 0.8R(s). The constant ratio of the gas thermal entropy to that of the DM implies that observations of the intracluster gas can provide an almost direct probe of the DM.
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	COOLING FLOW CLUSTERS ; X-RAY-CLUSTERS ; EXPANDING UNIVERSE ; DENSITY PROFILES ; STELLAR SYSTEMS ; HALOS ; SIMULATIONS ; EVOLUTION ; TEMPERATURE ; COLLAPSE
收录类别	SCI
语种	英语
WOS记录号	WOS:000245614800036
内容类型	期刊论文
源URL	[http://119.78.226.72/handle/331011/19511]
专题	上海天文台_星系宇宙学重点实验室
作者单位	1.Shanghai Astron Observ, Shanghai 200030, Peoples R China 2.Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA 3.Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel 4.Astrophys Inst Potsdam, D-14482 Potsdam, Germany 5.Univ Autonoma Madrid, Grp Astrofis, E-280049 Madrid, Spain
推荐引用方式 GB/T 7714	Faltenbacher, Andreas,Hoffman, Yehuda,Gottloeber, Stefan,et al. Entropy of gas and dark matter in galaxy clusters[J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,2007,376(3):1327-1334.
APA	Faltenbacher, Andreas,Hoffman, Yehuda,Gottloeber, Stefan,&Yepes, Gustavo.(2007).Entropy of gas and dark matter in galaxy clusters.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,376(3),1327-1334.
MLA	Faltenbacher, Andreas,et al."Entropy of gas and dark matter in galaxy clusters".MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 376.3(2007):1327-1334.