Exam 16: Normal and Active Galaxies: Building Blocks of the Universe

Active galaxies emit most of their energy in _ wavelengths than visible.

Is Hubble's tuning fork diagram a real evolutionary tool? Why?

There is evidence that a collision between a spiral and an elliptical galaxy has produced a radio galaxy.

What are Type I supernovae used for?

On average, active galaxies are rare and most are fairly distant from us.

Quasars appear to have very large redshifts, and are receding at nearly the speed of light.

X- ray observations of elliptical galaxies reveal large amounts of very hot _ in their interior.

In shape and component stars, elliptical galaxies are most like our own

A type Sa galaxy has a larger _ than type Sc.

While examining the spectrum of a galaxy, you find all the hydrogen lines are shifted to longer wavelengths. This galaxy is

Type Sc are the dustiest and flattest of the galaxies.

Hubble found a direct relation between a galaxy's velocity and distance.

The vast majority of galaxies in the universe are and .

For measuring the distances to galaxies within 17 Mpc, we rely primarily on _ variable stars.

The energy radiated by a typical quasar requires that its black hole accrete about

Irregular galaxies, although small, have large star- forming (HII) regions and much ongoing star formation for their size.

The most luminous quasars can give off _ times more light than our own Galaxy.

The Magellanic Clouds are good examples of the type of galaxy.

In active galaxies, their central engines may be temporarily fed by

A billion- solar- mass black hole would still have a radius of only