AST201H1 Lecture Notes - Lecture 4: Elliptical Galaxy, Bullet Cluster, Gravitational Lens

• School: UTSG
• Department: Astronomy & Astrophysics
• Course: AST201H1
• Professor: Michael Reid

Document Summary

Gravitational lensing showed that the bullet cluster had a lot more mass than what the x-ray gas emitted. To account for this unseen mass is dark matter. Wimps (small stuff, interact via gravity, no electromagnetic interaction) The milky way and andromeda will merge into one galaxy in about 4 billion years. Irregular- halo, may or may not have disk & bulge. There are some galaxies that don"t follow hubble"s law. Hubble law: the greater the distance of a galaxy, the greater it"s cosmological redshift. Therefore, in a gravitationally bound group, such as the local group, we do not expect the galaxy motions to follow hubble"s law. v = h0 x d: the y-axis of the hubble"s law graph is redshift of galaxies. Distant galaxies have greater redshift: hubble"s law shows that galaxies all appear to be moving away from us. Would an alien in a distant galaxy observe hubble"s.