Exam 18: Quasars and Other Active Galaxies

Why is it that astronomers will NOT see fluctuations in light output in times shorter than about 1 day when they observe an extragalactic source whose diameter is about 1 light-day?

Quasars have now been detected at redshifts so large that, if translated to "recession velocities," indicate motion away from the Milky Way Galaxy of

The energy output of a bright quasar is equivalent to

The mechanism that leads to the double-radio source phenomenon appears to be

When, by whom, and by what means was the first quasar detected?

The first three strong radio sources, discovered by Reber in the 1930s and 1940s, included all of these EXCEPT

The jets of material moving away from a supermassive black hole are generated by high pressures and temperatures at the base of the accretion disk. What causes these high temperatures?

The typical timescale for variability of a blazar (a parameter related to true physical size of these objects) is

Which of these statements MOST accurately characterizes the abundance of quasars over the universe's history?

If the central engine of a double-lobed radio source is a black hole swallowing matter from an accretion disk, where do the jets of matter come from that are observed traveling outward from the galaxy?

What is the MOST outstanding feature of a quasar compared with other objects in deep space?

Which of these phenomena will produce synchrotron radiation?

A spiral galaxy with a bright, starlike nucleus showing strong emission lines is called a

See Figure 18-10 in the text. NGC 1265, an active galaxy in the Perseus cluster, is described as a head-tail source because

The luminosity of the Milky Way Galaxy is about 10 billion times the luminosity of the Sun. During peak periods of brightness, the quasar 3C 279 has a luminosity about ten thousand times the luminosity of the Galaxy. Suppose the flux (energy per second per emitting area) from the Sun remains the same, but it grows in radius. How big would it have to be to produce the same luminosity as 3C 273 at its peak?

BL Lacertae objects appear to be

The energy output per second of a typical quasar is equal to that emitted by the Sun in

In which direction(s) are the jets of matter ejected from a supermassive black hole to produce the many effects surrounding quasars and active galaxies?

Does the presence of an AGN in a galaxy affect star formation rates in the galaxy?

Which one of these properties do Seyfert galaxies and the Milky Way Galaxy share?