Exam 24: Quasars and Active Galaxies

Why is it that, when we observe an extragalactic source whose diameter is about 1 light-day, we are unlikely to see fluctuations in light output in times shorter than about 1 day?

The energy output of a bright quasar is equivalent to:

Quasars, blazars, and double radio sources may well be the same kind of object, their different appearance simply being caused by their:

In the "unified model" of active galaxies, the main difference among quasars, blazars, and radio galaxies appears to be that:

The Sun's luminosity would have to increase by how many times for it to reach its Eddington limit?

One of the three astronomical objects that were first detected at radio wavelengths by Grote Reber in the 1930s and 1940s was:

The spectrum of a blazar shows:

The time of variation in the brightness of quasars can be as short as:

In order to appear superluminal, a few conditions must be satisfied by the material under observation. One of these is that:

What is a dead quasar flare?

Among galaxies with active galactic nuclei, Seyfert galaxies are:

If double radio sources, quasars, and blazars are considered to be the same basic object, why do they appear to us to have very different and distinct properties?

The major surprise about Cygnus A, one of the first three sources of strong radio emission detected by Grote Reber in the late 1930s, when examined with a large optical telescope, was that it:

Active galactic nuclei (AGN) include a variety of objects, but all are powered by:

What is the difference between a Seyfert galaxy and other AGNs?

Relatively rapid fluctuations (within 1 day) in the electromagnetic output of quasars is an indication of:

What would the mass of a supermassive black hole at the center of a quasar need to be, in terms of the solar mass, in order to produce a luminosity of 10¹² times that of our Sun, assuming that this luminosity is at the Eddington limit?

The quasar 3C 273 has a luminosity about 25 trillion times that of the Sun. Assuming this is the Eddington limit, what is the minimum mass of the active galactic nucleus (stated in solar masses)?

The quasar 3C 273 is believed to have a luminosity of about 2.5 × 10¹³ L_e at a distance of 620 Mpc. Suppose instead that it were a normal galaxy with a luminosity 1000 times smaller. How far away would it have to be to have the same apparent brightness it has now?

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