Definitely one of my favorite text on extragalactic astronomy, so fond of it that I actually owned a physical copy of the text. Today I am reading a subsection on stuff that I work on - X-ray radiation from clusters of galaxies :D

Was reviewing some basics in astronomy. Stuff such as the color-magnitude diagram for showing the relationship between the color and the brightness of stars (weird that astronomers call it color-magnitude coz it is really magnitude vs color diagram). Was also glad to see discussions of collisionless encounters (e.g. stuff ...