PCS 181 Chapter Notes - Chapter 4: Third Cambridge Catalogue Of Radio Sources, Large Magellanic Cloud, Irregular Galaxy

• School: Ryerson University
• Department: Physics
• Course: PCS 181
• Professor: Margaret Buckby

Document Summary

Week 4 note: more advanced class is pcs581. Luminosity = l = total energy emitted each second. R is radius of object in meters (m) There are ~20 constants of the universe (incl. Use luminosity (the brightness) to nd an approx. mass of galaxy. Mmw = ~(1x1011)(1. 99x1030 kg mass of the sun) But this doesn"t incl. mass that cannot be seen. Galaxy masses ranges from ~1x105 m to ~1x1013 m . Low mass of ~1x105 m means it is probably an irregular galaxy. The second mass ~1x1013 m is very large. Week 4 our galaxy, the milky way, has a mass of ~5. 8x1011m = 1. 2x1042 kg. This is incl. all the dark matter. The way we determine this is through celestial mechanics whereby you study the interactions with other galaxies and you deduce your ndings. Range of ages from old to young. Spiral arms will get greatly distorted because of the gravitational pull of incoming galaxy.