Study of Evolution of Galaxy Cluster and the Universe

虽然在z=0.0 ~ 1.0红移范围内的k_BT-L_X关系中没有发现CG演化的证据，在z<0.6红移范围内的k_BT-M_<gas>、k_BT-M_<Fe>、k_BT-A_<Fe>关系中也没有发现CG演化的证据，但在z>0.6处发现了一些演化的线索；距离最远的星团AXJ20I9+1127在z-1.0时的气体质量明显低于其他具有相同气体温度的星团，星团的铁质量与附近的星团相似。为了探讨星暴星系M82富金属气体的喷射机制，我们用ASCA对星系M82进行了观测。在0.5-10 keV波段的x射线表现出由高电离的镁、硅和硫组成的薄热谱线，以及延伸到高于10kev能量的硬尾。软x射线在空间上是扩展的，而硬x射线显示出一个未解决的点状结构，可能具有长期的通量变化。发射谱线的通量比和低能带的空间扩展结构表明，至少存在两个温度的薄热等离子体。薄热等离子体中的氧、氖、镁、硅、硫和铁的丰度被发现明显低于宇宙值。硬组分的光谱在空间上无法确定，可以很好地用吸收热轫致或吸收幂律模型来表示。然而，硬成分的来源尚不清楚。因此，我们于1996年用ASCA进行了监测观测。虽然软、中组分的x射线通量保持不变，但在10 ~ 1个月的不同时间尺度上，硬组分的x射线通量在3 <<1>> 10^<40> erg/s和1 <<1>> 10^<41> erg/s之间存在显著的时间变异性。硬组分的温度或光子指数也发生了变化。我们证明了硬分量的空间位置是M82的中心。用最高态光谱减去最低态光谱得到的变源光谱表明，该变源对NH- 10^<22> cm^<-2>有很强的吸收，说明该变源嵌入在M82的中心。所有这些都表明M82中存在一个低光度AGN。少

Although we found no evidence of CG evolution in the k_BT-L_X relation in the redshift range of z=0.0 - 1.0, nor in the k_BT-M_<gas>, k_BT-M_<Fe>, k_BT-A_<Fe> relation in z<0.6, some hints of evolution at z>0.6 are found ; the gas masses of the most distant cluster AXJ20I9+1127 at z-1.0 are significantly lower than those of the other CGs with the same gas temperature, the iron masses of the cluster is similar to that of nearby cluster.We observed starburst galaxy M82 with ASCA in order to investigate the ejection mechanism of metal rich gas. The X-rays in the 0.5-10 keV band exhibit a thin thermal spectrum with emission lines from highly ionized magnesium, silicon, and sulfur, as well as a hard tail extending to higher than l0keV energy. The soft X-rays are spatially extended, while the hard X-rays show an unresolved point-like structure with possible a long-term flux variability. The flux ratio of the emission lines and the spatially extended structure in the low-energy band indicate … More that at least two-temperature thin thermal plasmas are present. The abundances of the oxygen, neon, magnesium, silicon, sulfur, and iron in the thin thermal plasmas are found to be significantly lower than the cosmic value.The spectrum of the hard component, which is spatially unresolved, is well represented by an absorbed thermal bremsstrahlung, or an absorbed power-law model. However the origin of the hard component was unclear. Thus, we made a monitoring observation with ASCA in 1996. Although the X-ray flux of the soft and medium components remained constant, a significant time variability of the hard component was found between 3 <<1>> 10^<40> erg/s and 1 <<1>> 10^<41> erg/s at various time scales from 10 ks to a month. The temperature or photon index of the hard component also changed. We proved that the spatial position of the hard component is the center of M82. The spectrum of the variable source obtained by subtracting the spectrum of the lowest state from the highest state suggests the strong absorption of NH- 10^<22> cm^<-2>, which means the variable source is embedded in the center of M82. All these suggest that a low-luminosity AGN exists in M82. Less