ASTRON 2B03 Lecture Notes - Lecture 34: Bullet Cluster, Local Group, Dwarf Galaxy
28 Aug 2016
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Document Summary
In these collisions, large amounts of star formation occurs. The centres appear redder because the old stars live in the centres of the galaxies. The outer parts of collisions appear bluer because there is more star formation in those regions. Galaxy mergers are fundamental to building up the structure of the universe, but are relatively rare in the present universe. As you go to high red-shifts, galaxy mergers are more common. The whole event of a merger can take up to 500 million years. It may take billions of years to reach a steady state. Galaxy merging is an ongoing process, and was more frequent when things were closer together, and the galaxies themselves were smaller. What happens to constituents when galaxies collide: the gas heats up from collisions, and therefore glow, the stars will mostly pass by each other (distance between the stars is too large).
