PCS 581 Lecture Notes - Lecture 17: Starburst Galaxy, X-Ray, Solar Mass
Document Summary
Original proto galactic cloud varies in sizes. The higher the density the faster and more efficiently the star is formed: quickly turns all of its gas into stars. Low density stars are born slowly, inefficiently: not many stars form, gas remains to collapse and settle into a disk. Stars are born faster in gas that has a higher density. To definitely birth a spiral galaxy you need high density gas with a high spin. If it had collapsed while forming halo stars, which would be true of the outermost stars in the halo: mostly older stars (migrate further out in the accretion disk over ti. Streamers of stars could be old tidal tails from a previous collision. Tidal forces: the difference in gravity across the gravity. Gas sinks to the center, creating a burst of star formations. Supernovae, winds blow away the rest of the dust. End up with a big elliptical with very little gas, no discrete disk.
