Exam 27: Active Galaxies, Quasars, and Supermassive Black Holes

An astronomer who loved reading the Guinness Book of World Records when she was a child becomes obsessed with quasars and wants desperately to find the most distant quasar ever (the one with the largest redshift.) Where should she be looking to have the best chance of finding such a quasar?

After several decades of observation, astronomers have concluded that quasars are

Astronomers have established that quasars and active galaxies have a lot of mass at their centers in a very small volume of space. Why can't this mass be in the form of a cluster of stars that are quite close to each other?

How are galaxies and quasars related?

What method would astronomers use to find the distance to a remote quasar?

Today, astronomers find compelling evidence that the energy source of the quasars and active galaxies is

Why do astronomers think that there are fewer quasars today than there were billions of years ago?

How do astronomers explain the energetic jets that come out of quasars and active galactic nuclei in opposite directions?

If quasars are at the distances most astronomers believe they are, then (for the most luminous ones) their luminosities must be:

Today we know that what all quasars have in common is that they appear to be small sources of energy with

What observation in astronomy, made AFTER the discovery of quasars, was a big help to astronomers in figuring out what quasars really were?

The Hubble Space Telescope has enabled astronomers to explore an active galaxy such as M87 in remarkable detail. Which of the following observations of M87 is NOT an important part of the web of evidence that shows it must have a supermassive black hole at the center?

How can supermassive black holes at the centers of galaxies help new stars to form in that galaxy?

An astronomer claims that the large redshifts of all quasars are caused by some new mechanism and not the expansion of the universe. The redshift tells us nothing, he says, about where any quasar is located. Which of the following would be a way to disprove his view of quasars?

How do quasars demonstrate that the universe evolves with time?

A distant quasar shows a large redshift -- one so large, in fact, that the features we now see in the visible-light region of the spectrum would be invisible to us, were it not for the redshift. What band of the electro-magnetic spectrum were these features most likely in, before the spectrum was redshifted?

If a nearby galaxy still acts like a quasar today, what is the most likely explanation?

When astronomers make counts of how many quasars there are at different distances from us, what do they find?

When quasars "shine" (in visible light and other kinds of radiation) with a lot of energy, where (what location) does this huge amount of energy come from?

Which of the following observations is a convincing argument for the idea that quasars are located inside galaxies?