Consider a normal spiral galaxy such as the Milky Way. (la) Show that the rigid-body rotation observed near the Galactic
Posted: Fri Apr 29, 2022 11:02 am
Consider a normal spiral galaxy such as the Milky Way. (la) Show that the rigid-body rotation observed near the Galactic center is consistent with a spherically symmetric mass distribution with constant density near the Galactic centre. What is expected to be the angular speed of the rotation in this case? (12 marks] (1b) Show that the roughly flat rotation curves observed for spiral galaxies at large distances from the center are consistent with a spherically symmetric mass distribution with a density that is proportional to r-2 [12 marks] (1c) In practice, the mass distribution in the dark matter halo is sometimes taken to have the form Co p(r) = a2 + 2 where Co and a are constants. Does this distribution contadict the observation of rigid-body rotation near the Galactic center? Why or why not? [6 marks]