Chandra Observations of the A3266 Galaxy Cluster Merger
Chandra Observations of the A3266 Galaxy Cluster Merger
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DOI：
10.1086/342115
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发表时间：
2002-07
期刊：
影响因子：
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通讯作者：
M. Henriksen;E. Tittley
中科院分区：
文献类型：
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作者：
M. Henriksen;E. Tittley
利用钱德拉X射线天文台上的ACIS对A3266星系团进行了30,000秒的X射线观测，分析了星系团合并的几个新见解。团内介质具有非单调递减的径向丰度分布。我们认为，丰度增强的最合理的起源是未混合的，高丰度的子星系团气体的合并。富集包括两个阶段：在子星系团合并过程中，一种丰度较高的物质偏离中心沉积，随后是一种强烈的局部化的星系团内风，这种风的作用是驱逐轻元素，产生观测到的丰度增强。风是需要考虑的重元素丰度的增加和缺乏增强的气体密度。风的动力学证据包括：（1）垂直于合并轴的大规模低表面亮度特征，似乎是远离主星团中心的西北方向的不对称气流模式;（2）相反方向的压缩气体（朝向集群中心）;以及（3）温度图中可见的最热区域与所提出的合并几何形状和所得气流一致的事实。主星系团中心区域的钱德拉数据显示了一个稍微冷却的非对称区域，该区域以中心的cD星系为中心，并与合并轴对齐，直接将cD的动力学状态与合并联系起来。总的来说，高光谱/空间分辨率的钱德拉观测支持了我们先前的假设，即我们正在观察天空平面上的一个小合并。
Analysis of a 30,000 s X-ray observation of the A3266 galaxy cluster with the ACIS on board the Chandra X-Ray Observatory has produced several new insights into the cluster merger. The intracluster medium has a nonmonotonically decreasing radial abundance profile. We argue that the most plausible origin for the abundance enhancement is unmixed, high-abundance subcluster gas from the merger. The enrichment consists of two stages: off-center deposition of a higher abundance material during a subcluster merger followed by a strong, localized intracluster wind that acts to drive out the light elements, producing the observed abundance enhancement. The wind is needed to account for both an increase in the heavy-element abundance and the lack of an enhancement in the gas density. Dynamical evidence for the wind includes (1) a large-scale, low surface brightness feature perpendicular to the merger axis that appears to be an asymmetric pattern of gas flow to the northwest, away from the center of the main cluster; (2) compressed gas in the opposite direction (toward the cluster center); and (3) the fact that the hottest regions visible in the temperature map coincide with the proposed merger geometry and the resultant gas flow. The Chandra data for the central region of the main cluster show a slightly cooler, filamentary region that is centered on the central cD galaxy and is aligned with the merger axis directly linking the dynamical state of the cD to the merger. Overall, the high spectral/spatial resolution Chandra observations support our earlier hypothesis that we are viewing a minor merger in the plane of the sky.