论文标题
在Abell 98中发现了群间细丝中的合并前冲击
Discovery of a pre-merger shock in an intercluster filament in Abell 98
论文作者
论文摘要
我们使用深（227 ks）Chandra观测值报告了在早期合并集群Abell 98中对轴向合并休克的第一次明确检测。冲击约为Abell 98的北部亚集团向南约420 kpc，介于北部和中央子集群之间，其马赫数为M $ \ $ \ $ 2.3 $ \ pm $ 0.3。当在合并过程的早期阶段捕获两个子集群时，我们发现轴向合并冲击阵线在形成大型星系群的形成时揭示了一个关键时期。我们发现，震动后区域中的电子温度有利于即时无碰撞模型，其中通过与磁场的相互作用，在冲击方面强烈加热电子。我们还报告了检测到群间气体的检测，温度为Kt = 1.07 $ \ pm $ 0.29 kev，沿着Abell 98的合并轴。灯丝中气体的测量属性与先前的观察值和数值模拟相一致。星系群。
We report the first unambiguous detection of an axial merger shock in the early-stage merging cluster Abell 98 using deep (227 ks) Chandra observations. The shock is about 420 kpc south from the northern subcluster of Abell 98, in between the northern and central subclusters, with a Mach number of M $\approx$ 2.3 $\pm$ 0.3. Our discovery of the axial merger shock front unveils a critical epoch in the formation of a massive galaxy cluster, when two subclusters are caught in the early phase of the merging process. We find that the electron temperature in the post-shock region favors the instant collisionless model, where electrons are strongly heated at the shock front, by interactions with the magnetic field. We also report on the detection of an intercluster gas filament, with a temperature of kT = 1.07 $\pm$ 0.29 keV, along the merger axis of Abell 98. The measured properties of the gas in the filament are consistent with previous observations and numerical simulations of the hottest, densest parts of the warm-hot intergalactic medium (WHIM), where WHIM filaments interface with the virialization regions of galaxy clusters.
