By comparing different models of the shock, the authors derive a “mach number” M≈2.4, which says the clusters are colliding at 2.4 times the speed of sound. That’s quite a sonic boom, particularly given that the speed of sound in the hot plasma is around 2 million miles per hour!
The author revisits a seminal article that reviews our understanding of AGN feedback, and comes out extremely impressed with the status quo (and the parallels with fictional universes).
This article explores the utility of galaxy clusters as a probe for precision cosmology, by reviewing some of the seminal literature in the field. Somewhere along the way, a symphony is heard.
Omega Centauri is a huge globular cluster, so much so that some astronomers think it could be the remnant of a disrupted dwarf galaxy. We will see that this is not necessarily true.
Unlike most astrophysicists today, this one did go observing for a change. And what he finds there is out of this world. Literally.
The XXL Survey is here as the rightful successor to the XMM-Newton survey that gave us a unique and extravagant look into the high-energy universe. Here, we look at some of the observations that the XXL has to offer!