发表机构
Institute of High Energy Physics, Chinese Academy of Sciences; Nanjing Normal University; Beijing Normal University（中国科学院高能物理研究所; 南京师范大学; 北京师范大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究利用EP - FXT对阿贝尔1795进行深度X射线观测，测量其径向温度剖面，通过表面亮度残差图等揭示螺旋结构和弱激波等子结构，用二元合并场景解释，表明松弛星系团能保留动力学活动特征。
AI 中文摘要
我们展示了使用爱因斯坦探针后续X射线望远镜（EP - FXT）对附近X射线发光星系团阿贝尔1795进行的深度X射线观测，总曝光时间为480千秒。利用EP - FXT的大视场和低粒子背景，我们直接测量了A1795直至\(R_{200}\)的径向温度剖面，其在6角分内随半径增加，然后向更大半径逐渐下降。表面亮度残差图和二维热力学图揭示了从星系团核心向东南延伸的顺时针螺旋结构，这与晃动引起的冷锋一致。在西北，表面亮度增强区域呈现出类似弧形的高温特征，温度和密度衍生的马赫数都支持这是一个弱激波。这些子结构可以用二元合并场景来解释。我们的结果表明，像A1795这样的松弛星系团仍可保留动力学活动的特征。
英文摘要
We present deep X-ray observations of the nearby X-ray-luminous galaxy cluster Abell 1795 obtained with the Einstein Probe Follow-up X-ray Telescope EP-FXT, with a total exposure time of $\sim 480$ ks. Exploiting the large field of view and low particle background of EP-FXT, we directly measured the radial temperature profile of A1795 out to $R_{200}$ with full azimuthal coverage, which was shown to increase in line with the radius within 6' and then gradually decline toward larger radii. The surface-brightness residual map and 2D thermodynamic maps reveal a clockwise spiral structure extending from the cluster core towards the south-east, which traces low-temperature and low-entropy gas, which is also consistent with sloshing-induced cold fronts. In the north-west, the surface-brightness-enhanced region exhibits an arc-like high-temperature feature and both the temperature-derived and density-derived Mach numbers support the assumption that it is a weak shock. These substructures can be explained by a binary merger scenario: the perturbing subcluster induces sloshing during its first passage past the primary core and its subsequent return passage through the ICM might drive the shock towards the north-west. Our results indicate that relaxed galaxy clusters such as A1795 might still retain signatures of dynamical activity.
Comments10 pages, 11 figures. Accepted for publication in A&A
