Large scale extended X-ray emission from the Virgo cluster of galaxies
Large scale extended X-ray emission from the Virgo cluster of galaxies
复制标题
室女座星系团大规模扩展 X 射线发射
作者：
S. Takano;H. Awaki;K. Koyama;H. Kunieda;Y. Tawara;S. Yamauchi;K. Makishima;T. Ohashi
X 射线观测显示，高温稀薄气体渗透到许多星系团中。如果气体处于流体静力平衡，它就会追踪星团的引力势。星系团的 X 射线映射可用于估计星系团的总质量，包括暗物质及其空间分布。先前对室女座星团（最近的丰富星系团）发射的 X 射线的观测表明，它集中在距 M87（该星系团中的主导星系）约 100 弧分的范围内2,3。由于室女座星团的光学图像直径约为 12°，因此 X 射线发射被认为与 M87 有关，而不是与整个星团有关。在这里，我们报告了由 Ginga 卫星绘制的处女座的初步地图，该地图显示扩展的 X 射线发射与星团的光学范围一样广泛分布。这表明室女座星团的星系浸没在热的扩散星团内介质中。
HOT, tenuous gas is revealed, by X-ray observations1, to permeate many clusters of galaxies. If the gas is in hydrostatic equilibrium, it traces the cluster's gravitational potential. X-ray mapping of clusters of galaxies can be used to estimate the total cluster mass, including dark matter, as well as its spatial distribution. Previous observations of X-ray emission from the Virgo cluster, the nearest rich cluster of galaxies, showed it to be concentrated within ∼100 arcmin of M87, the dominant galaxy in the cluster2,3. Because the optical image of the Virgo cluster is ∼ 12° in diameter, the X-ray emission was thought to be associated with M87 rather than with the cluster as a whole. Here we report a preliminary mapping of Virgo made by the Ginga satellite which shows the extended X-ray emission as broadly distributed as the cluster's optical extent. This indicates that the galaxies of the Virgo cluster are immersed in a hot diffuse intracluster medium.