论文标题
预合并星系集群Abell 98
Gas sloshing and cold fronts in pre-merging galaxy cluster Abell 98
论文作者
论文摘要
我们介绍了合并前星系群Abell 98的深度观测。Abell98是一个复杂的合并系统。尽管北部（A98N）和中央子截面（A98S）沿着南北方向合并，而A98S正在进行单独的后期合并，并带有两个不同的X射线核心。我们报告了A98N和A98S东部核心中气体荡妇螺旋的检测。我们在A98N中检测到两个冷前边缘。我们发现沿A98S西部核心东部核心的东部方向的东方方向另外两个表面亮度边缘。我们测量这些边缘的温度和气体密度，发现东部边缘似乎是冷锋，而西部边缘是一个冲击阵线，其马赫数为$ \ cal {m} $ $ \ $ \ $ 1.5。我们检测到与A98S东部核心相关的X射线发射的“尾巴”。我们的尺寸表明，尾巴比周围气体凉爽，以4.2- $σ$的水平凉爽，这表明尾巴是已剥离的凉爽核心残留物的一部分。
We present deep Chandra observations of the pre-merger galaxy cluster Abell 98. Abell 98 is a complex merging system. While the northern (A98N) and central subclusters (A98S) are merging along the north-south direction, A98S is undergoing a separate late-stage merger, with two distinct X-ray cores. We report detection of gas sloshing spirals in A98N and in the eastern core of A98S. We detect two cold front edges in A98N. We find two more surface brightness edges along the east direction of the eastern core and west direction of the western core of A98S. We measure the temperatures and gas densities across those edges, and find that the eastern edge appears to be a cold front while the western edge is a shock front with a Mach number of $\cal{M}$ $\approx$ 1.5. We detect a "tail" of X-ray emission associated with the eastern core of A98S. Our measurement indicates that the tail is cooler than the surrounding gas at a 4.2-$σ$ level, suggesting the tail is part of a cool core remnant that has been ram-pressure stripped.
