Multi-wavelength Investigations of Galaxy-Hot Plasma Interactions in Clusters of Galaxies

我们通过对星系团中的三种主要质量成分（即星系、热ICM和暗物质）进行更全面的研究，继续并扩展了研究课题——星系向星系团中心的宇宙学落入（最初由Makishima et al. 2001提出）。我们与中国国家天文台的光学天文学家（韩教授和文博士）合作，收集了340个红移范围为0.1-0.5的星系团样本。样本的大小是Gu et al.（2013）中使用的样本的10倍。在这项工作中，我在分析x射线和光学数据方面发挥了核心作用。继Gu et al.（2013）之后，我们已经发现了宇宙学时间尺度上的重大演变：相对于ICM和暗物质，星系已经集中在时间中心，而ICM相对于暗物质一直在膨胀，即使它们一直在辐射。这种演化不仅仅是由引力效应驱动的，比如星系和星系团物质之间的动态摩擦。研究结果将很快提交给《天体物理学杂志》。参考文献：Makishima， K.等。2001，中国生物医学工程学报，53 (3),401；顾磊等。2013,ApJ, 767, 157；顾磊等。2014,in prep.。

We have continued and extended the research topic, the cosmological infall of galaxies into the centre of galaxy clusters (originally proposed by Makishima et al. 2001), by carrying out a much more comprehensive study on the three main mass components i.e., galaxies, hot ICM, and dark matter, in the galaxy clusters.In collaborating with optical astronomers (Prof. Han and Dr. Wen) in National Observatory of China, we compiled a sample of 340 galaxy clusters in redshift range of 0.1-0.5. The size of the sample is 10 times as the one used in Gu et al. (2013). In this work I played a central role in analyzing both X-ray and optical data. We have detected, following Gu et al. (2013), a significant evolution on a cosmological timescale: galaxies have been centrally concentrated with time relative to the ICM and dark matter, while the ICM has been expanding compared to dark matter even they keep radiating. This evolution is not solely driven by gravitational effects such as dynamical friction between galaxies and cluster matters. The result will be submitted soon to the Astrophysical Journal.References: Makishima, K. et al. 2001, PASJ, 53, 401; Gu, L. et al. 2013, ApJ, 767, 157; Gu, L. et al. 2014, in prep.