Read Chapter 21
1.) How is the evolution of a spiral galaxy similar to that
of a protostar?
a.) In both cases a cloud of gas gravitationally contracts
b.) Early on, the material cools by radiation
c.) Both "spin-up"
d.) All of the above
e.) None of the above
2.) Why do some protogalaxies evolve into spiral galaxies
while others evolve into elliptical galaxies?
a.) Because the amount of angular momentum differs between
protogalaxies
b.) Because the fraction of metals atoms in the gas differs between
protogalaxies
c.) Both of the above
d.) None of the above
3.) How do astronomers explain the existence of irregular galaxies?
a.) As two galaxies are merging, they look like an irregular galaxy
b.) Before a protogalaxy has finished forming its disk, it looks irregular
c.) Galaxies with strong Active Galactic Nuclei look irregular
d.) All of the above
e.) None of the above
4.)
a.) What role do mergers play in making spiral galaxies?
b.) What role do mergers play in making elliptical galaxies?
c.) What role do collisions or mergers play in making irregular galaxies?
d.) What role do collisions or mergers play in making starbursts?
5.)
a.)
What is a galactic wind?
b.)
What causes a galactic wind?
6.)
a.) How is a galactic wind similar to a superbubble in the
Milky Way galaxy?
b.) How is a galactic wind different from a superbubble in
the Milky Way galaxy?
7.) Which type of galaxy has
a supermassive black hole and extremely bright accretion disk
in its center?
a.) A quasar
b.) A radio galaxy
c.) A galaxy having an Active Galactic Nuclei
d.) All of the above
e.) None of the above
8.) Describe the jets and lobes of a radio galaxy
9.) Why do we think that the ultimate
energy source for a radio galaxy is material
falling into a huge black hole?
10.) What sort of observational evidence supports the
idea that supermassive black holes exist?
11.) Regarding the gas clouds residing between the Milky Way
and the most distant observable quasars:
a.) Usually the clouds that are furthest from the Milky Way have the least
amounts of neutral hydrogen gas
b.) Usually the clouds that are furthest from the Milky Way have the smallest
fractions of metal atoms
c.) Usually the clouds that are furthest from the Milky Way have the least
redshifted hydrogen absorption lines
d.) All of the above
e.) None of the above