Galaxy evolution in the distant universe

点击翻译按钮获取中文摘要

A galaxy cluster is very much like a galaxy city - a true urban environment where galaxies co-exist at much higher density than their rural counterparts in non-cluster (labelled "field") locations. Galaxy clusters pose a number of puzzling questions: how have they grown more massive with time and by searching for distant clusters can we observe their growth directly? In addition, how have the cores of rich galaxy clusters come to be dominated by populations of bright, red elliptical galaxies (as opposed to the blue, spiral-rich field)? I am part of a large, international team of researchers who are identifying new galaxy clusters using the XMM-Newton space observatory. XMM detects galaxy clusters by virtue of their incredibly bright X-ray emission and reveals a strange, new Universe very different to our naked eye view of the night sky. I am leading the effort to discover the most distant galaxy clusters known - the light from some of which has taken over half the age of the Universe to reach us. Each image of a galaxy cluster is like a snapshot of the distant past and by comparing the "baby photos" of young galaxy clusters we can learn about the physics that shaped them. Together with my graduate students and my international collaborators we are privileged to have a direct view back to the time when these great galaxy-cities were under construction.