Deck 17: Supermassive Black Holes and Active Galaxies

Question 1

The structure of black hole jets is believed to be controlled by magnetism.

Answer 1

True

Question 2

Supermassive black holes have weaker gravity than stellar-mass black holes, producing slower spins for the infalling matter.

Answer 2

False

Question 3

Supermassive black holes are very large, the most massive even larger than our Solar System.

Answer 3

False

Question 4

The luminosity of a Seyfert galaxy varies with a regular period of months or years.

Question 5

Active galactic nuclei were first found through observations in the ____ wavelength band.

A) visible
B) infrared
C) X-ray
D) radio
E) ultraviolet

Question 6

Normal galaxies in the present never went through an active galaxy phase.

Question 7

Seyfert galaxies appear similar to normal spirals with extremely luminous cores.

Question 8

Quasars are radio sources that look like stars in visible-light photographs.

Question 9

The unified model of active galactic nuclei focuses on differences caused by the age of the central black hole.

Question 10

The size of a galaxy's central black hole is proportional to the mass of its disk.

Question 11

Black holes erupt when matter flows into their accretion disk.

Question 12

Quasars are isolated supermassive black holes, and not associated with galaxies.

Question 13

Matter flowing into a black hole cools until it is accelerated into a jet.

Question 14

Seyfert galaxies are____

A) spiral galaxies with unusually luminous nuclei
B) elliptical galaxies with very broad emission lines
C) explained by the double-exhaust model
D) extremely luminous objects with high redshifts only
E) glowing green gases due to excitation from energy from an active core

Question 15

The luminosity of a Seyfert galaxy varies with a regular period of months or years.

Question 16

Double-lobed radio galaxies are an effect of black hole jets.

Question 17

Most supermassive black holes are dormant.

Question 18

Collisions in the early Universe were rare.

Question 19

The broad emission lines of Seyfert galaxies imply high gas speeds in the nucleus.

Question 20

Quasars are caused by galaxy collisions in the early Universe.

Question 21

Quasars have a(n) ____.

A) extremely high blueshift
B) moderate blueshift
C) undetectable Doppler shift
D) moderate redshift
E) extremely high redshift

Question 22

Seyfert galaxies____.

A) often have unique shapes spectra suggesting fast-moving, hot gas
B) have no gas and dust in their spiral arms
C) are associated with pairs of radio sources
D) have visible jets of matter coming from their cores
E) are always isolated galaxies

Question 23

The energy output of a Seyfert galaxy____.

A) changes slowly with a period of weeks
B) is a hundred times the luminosity of the entire Milky Way
C) is noticeable only in the infrared
D) comes from starburst effects
E) is concentrated in the spiral arms

Question 24

Seyfert galaxies are always ____ galaxies.

A) dwarf
B) irregular
C) spiral
D) elliptical
E) flocculent

Question 25

The high luminosity of a Seyfert galaxy____.

A) comes from the halo of the galaxy
B) is distributed through the spiral arms
C) is spread through the central bulge
D) is concentrated in a very small region of the nucleus
E) varies over the course of years

Question 26

Gas falling into a black hole becomes ____.

A) hot, due to an increase in speed and molecular collisions
B) hot, due to radiation from the black hole
C) compacted into solid matter by tidal forces.
D) cool, due tothe loss of gravitational energy.
E) cool, due tothe emission of infrared photons

Question 27

When they were first discovered, quasars appeared to be____.

A) small, star-like objects associated with radio emission
B) pairs of radio sources
C) elliptical galaxies with an X-ray emitting halo
D) clouds of gas glowing with green emission lines
E) linear jets of matter

Question 28

Many galaxies with erupting black holes are found ____.

A) in poor clusters with little intergalactic gas
B) isolated in space
C) in one of a pair of orbiting galaxies
D) very close to the Milky Way galaxy
E) in the Local Group

Question 29

A supermassive black hole erupts when ____.

A) i t collides with a neutron star
B) magnetic fields form tubes to channel the jets
C) the accretion disk tilts to a new angle
D) a sudden flood of matter flows inward producingan accretion disk
E) starburst events irradiate the accretion disk with new energy

Question 30

The formation process for supermassive black holes is linked with the formation of galactic ____.

A) disks
B) clusters
C) central bulges
D) coronae
E) halos

Question 31

Matter falling into a black hole arranges itself in the shape of a ____.

A) spherical shell that is thick at the edges and thin closer to the center
B) spherical shell that is thin at the edges and thick closer to the center
C) disk that is thick at the outer edge, thin along the inner ring
D) disk that is thin at the outer edge and thick closer to the center
E) disk that is thin from the outer edge to the center

Question 32

Supermassive black holes erupt in ____.

A) any type of galaxy, and at random times
B) elliptical galaxies only, when the last of their gas and dust is consumed
C) galaxies that have been part of a collision or merger
D) spiral galaxies only, during a burst of star formation
E) irregular galaxies

Question 33

The formation of a galactic central bulge is believed to ____.

A) be a slow steady process lasting billions of years
B) start after the formation of spiral arms
C) be a violent process which adds mass to the central black hole
D) begin when the central black hole has reached mature size
E) continue throughout the galaxy's life body

Question 34

Quasars are____.

A) spiral galaxies with unusually luminous nuclei
B) elliptical galaxies with very broad emission lines
C) explained by the double-exhaust model
D) extremely luminous objects with high redshifts
E) glowing green gases due to excitation from energy from an active core

Question 35

A supermassive black hole that is erupting____.

A) will consume all gas and dust in the galaxy
B) will heat the gas in the cluster until it all escapes
C) is fed by the intergalactic gas of the cluster
D) may push its accretion disk away and choke off the eruption
E) will push other galaxies away from its parent galaxy

Question 36

What produces the lobes in double-lobed radio galaxies?

A) an accretion disk
B) a starburst event
C) black-hole jets
D) synchrotron radiation
E) high redshifts

Question 37

Double-lobed radio galaxies are____.

A) spiral galaxies with unusually luminous nuclei
B) elliptical galaxies with very broad emission lines
C) explained by the double-exhaust model
D) extremely luminous objects with high redshifts
E) glowing green gases due to excitation from energy from an active core

Question 38

What is the best description of Hanny's Voorwerp?

A) spiral galaxies with unusually luminous nuclei
B) elliptical galaxies with very broad emission lines
C) a type of double-exhaust model
D) extremely luminous objects with high redshifts
E) glowing green gases due to excitation from energy from an active core

Question 39

A unified model of active galaxy cores can explain different types of Seyfert galaxies, quasars and other active galaxy types by differences in the ____.

A) mass of the supermassive black hole
B) size and thickness of the accretion disk
C) magnetic flux strength in the jets
D) amount of dust in the accretion disk
E) tilt of the accretion disk to the line of sight

Question 40

The motion of gas in accretion disks and jets is ____.

A) well explained by Einstein's theory of general relativity
B) poorly understood, but may depend on magnetism
C) well explained by Kepler's laws.
D) poorly understood, but may depend on relativity
E) well explained by electromagnetic wave theory

Question 41

Different types of active galaxies are caused by different orientations of the central black hole's _______________.

Question 42

In the unified model, an accretion disk viewed from the side will cause ____ to be present in the spectrum of a Seyfert galaxy.

A) narrow absorption lines
B) broad absorption lines
C) narrow spectral lines
D) broad emission lines
E) no absorption lines

Question 43

Figure 17-12 (for the following questions) Most quasars have a redshift of ____.

A) less than 1.0
B) between 1.0 and 2.0
C) between 2.0 and 3.0
D) between 3.0 and 4.0
E) greater than 4.0

Question 44

Active galaxies are the result of galactic _______________.

Question 45

What is the cause of the lobes in a double-lobed radio galaxy?

Question 46

Figure 17-12 (for the following questions) The accompanying graph shows that quasars formed ____.

A) starting after the formation of the Universe and peaking long ago, with almost none occurring today
B) just after the formation of the Universe, dropping steadily to none occurring today
C) steadily through time from the early Universe until today
D) after the formation of the Universe, with more and more occurring over time
E) long after the formation of the Universe, peaking before the present day

Question 47

Active galaxies were first discovered by observations in the _______________ wavelength band.

Question 48

Quasars are common in the early Universe because ____ at that time.

A) galactic collisions were more frequent
B) black hole collisions were more frequent
C) gas and dust clouds were denser
D) galaxies were more isolated
E) central bulges were larger

Question 49

Quasars ____.

A) are common at all ages of the Universe
B) are the early stages of what become Seyfert galaxies
C) disrupt galactic formation and become isolated black holes
D) are an early stage of the formation of common galaxies
E) are formed from double-lobed radio galaxies

Question 50

A spiral galaxy with an extremely luminous, active core is called a(n) _______________ galaxy.

Question 51

Some active radio galaxies exhibit _______________ of gas heated by jets.

Question 52

Black hole jets are believed to be focused and confined by the enclosing magnetic _______________.

Question 53

Matter falling into a black hole converts _______________ energy into thermal energy.

Question 54

The Doppler effect in the spectra of quasars show very high _______________.

Question 55

Matter falling into a black hole forms a(n) _______________ disk.

Question 56

A galaxy's supermassive black hole represents about ____ for elliptical galaxies.

A) half a percent of the mass of the disk
B) five percent of the mass of the central bulge
C) half a percent of the mass of the central bulge
D) five percent of the mass of the disk
E) half a percent of the dark matter in the corona

Question 57

Astronomers conclude that quasars must come from the earliest phases of the Universe because they ____.

A) have supermassive black holes
B) are colliding with other galaxies
C) create jets
D) have large redshifted spectra
E) have a fluctuating luminosity

Question 58

Active galaxies are believed to be the product of collisions and interactions because ____.

A) they are always seen in contact with another galaxy
B) the transfer of matter would explain the black hole eruption
C) the collision of individual stars would explain the black hole eruption
D) central bulges are formed by collisions
E) supermassive black holes are necessary for galactic collisions

Question 59

Ultraluminous radio sources associated with small visible-light objects are called _______________.

Question 60

What two things are unusual about the luminosity of the core of a Seyfert galaxy?

Question 61

What is the unified model of active galactic nuclei? How does it explain differences in the continuous spectrum and emission lines of an active galactic nucleus?

Question 62

Why are active galaxies assumed to be associated with galactic collisions?

Question 63

Explain why the observable properties of quasars imply that they are objects from the early Universe controlled by supermassive black holes.

Question 64

Why do astronomers believe that galactic collisions cause active galactic nuclei?

Question 65

Discuss the discovery of Seyfert galaxies and their observable properties.

Question 66

Why are rapid fluctuations in an active galaxy's luminosity evidence for a supermassive black hole?

Question 67

How and when did supermassive black holes form?

Question 68

Why do astronomers conclude that quasars are very far away?