Deck 24: Galaxies: Building Blocks of the Universe

Question 1

The smallest dwarf irregular galaxies are no richer in stars than the largest known globularclusters.

Answer 1

True

Question 2

The Tully-Fisher relation is much like the mass-luminosity relationship, except that thegalaxy's rotation is used to find its mass; the greater the mass, the faster the rotation rate.

Answer 2

True

Question 3

Type Sc are the dustiest of the galaxies.

Answer 3

True

Question 4

The first hint that the universe might be expanding came from Vesto Slipher's work with thespectra of spiral nebulae in 1912.

Question 5

The first clue to the significance of quasars came from the discovery that some of these"stars" were much stronger radio sources than any normal star.

Question 6

M-31 in Andromeda is a slightly bigger version of our own Milky Way.

Question 7

The expansion of the universe means that stars in our Milky Way Galaxy are gettingincreasingly farther apart.

Question 8

Our own Local Group is dwarfed by the much larger Virgo Cluster, about 50 million light-years distant.

Question 9

Quasars can emit as much as thousands of times as much energy as normal galaxies.

Question 10

While our two companions, the Magellanic Clouds, are irregulars, Andromeda's twocompanions, M-32 and M-110, are dwarf ellipticals.

Question 11

Active galactic nuclei are usually powered by supermassive black holes.

Question 12

Irregular galaxies, although small, have large H II regions and much ongoing star formationfor their size.

Question 13

The latest evidence from 2MASS suggests our own Milky Way is type SBb.

Question 14

There is very little interstellar gas or dust in most elliptical galaxies.

Question 15

Most galaxies are spirals.

Question 16

If the redshift is an accurate indication of the distance to that galaxy, then this is considered acosmological redshift.

Question 17

Most galaxies are members of some sort of cluster of galaxies.

Question 18

Type I supernovae can be used to determine distances to galaxies much better than type IIsupernovae.

Question 19

Orientation counts; if looking down the jets of an active core, we see a blazar.

Question 20

Galaxies are classified into types solely on the basis of their color.

Question 21

In Hubble's classification, which type of galaxy has a small bulge and loose, widely spread,poorly defined spiral pattern?

A)SO
B)S9
C)Sa
D)Sc
E)SBw

Question 22

The Large and Small Magellanic Clouds fall into Hubble's class:

A)SBc.
B)Pec.
C) $\text { E6. }$
D) $\text { Irr I. }$
E) $\text { E3. }$

Question 23

Within the boundaries of the constellations Coma and Virgo are found:

A)all the galaxies in the Local Group.
B)the most distant known quasars.
C)the largest nearby superclusters of galaxies.
D)the closest red dwarfs to the Sun.
E)the Large and Small Magellanic Clouds.

Question 24

Some lobes of radio galaxies are in fact moving faster than the speed of light.

Question 25

The greatest variation in size, mass, and luminosity occurs in:

A)globular clusters.
B)elliptical galaxies.
C)spiral and barred spiral galaxies.
D)type I vs. type II irregulars.
E)Seyfert galaxies.

Question 26

In this diagram, the galaxy at the left side is a(n):

A)Seyfert.
B)Spiral.
C)Barred spiral.
D)Elliptical.
E)Irregular.

Question 27

When mass is accreted into a black hole, how much total mass-energy can be radiated away?

A).007%
B).08%
C)1.4%
D)20%
E)50%

Question 28

An intermediately wound barred spiral galaxy would, in Hubble's system, be:

A) $\text { BS2. }$
B) $\text { BSE.5. }$
C)SBb.
D)S2B.
E)SIrr.

Question 29

The flattest of the ellipticals are class:

A)E0.
B)SBO.
C)E7.
D)E9.
E)SBF.

Question 30

Which of the following is true about the ages and masses of spiral and elliptical galaxies?

A)Ellipticals are all older and more massive than spirals.
B)Spirals are older, and much more massive than ellipticals.
C)Both types are about the same age, but spirals vary less in mass.
D)Spirals are younger and much more massive than any elliptical.
E)Ellipticals are older, and show a far wider range of masses than do spirals.

Question 31

Which type of galaxy has a stellar disk, but without gas and dust?

A)E0
B)E7
C)Irr I
D) $\text { S0 }$
E)SE

Question 32

A spherical galaxy, like M87, which looks like a monster globular cluster, is type:

A) $\mathrm { S } 0$
B)ES.
C) $\text { E0. }$
D) $\text { ES1. }$
E) $0 \mathrm {~V}$

Question 33

Astronomers observe unobscured X-rays generated in active galactic nuclei.

Question 34

What is the nearest huge cluster of galaxies to our Local Group?

A)Coma Cluster
B)Centaurus Cluster
C)Virgo Cluster
D)Orion Nebula
E)Hercules Cluster

Question 35

Which of these would be made up of only Population II stars?

A)elliptical galaxies
B)Irr type I
C)Irr type II
D)barred spirals
E)Seyfert spirals

Question 36

Most of the galaxies in the Local Group are:

A)big spirals like our Galaxy and $\text { M31. }$
B)small spirals like $\text { ?33 }$ nd the LMC.
C)small irregulars like the Magellanic Clouds.
D)active galaxies like Centaurus A.
E)small ellipticals like the companions to M31 in Andromeda.

Question 37

In Hubble's classification, which type of galaxy has no stellar disk and no gas or dust?

A) $\text { E0 }$
B) $\text { S0 }$
C)Sa
D)SBc
E)E9

Question 38

The Milky Way is often considered to be an intermediately wound, barred spiral, whichwould be type ________ according to Hubble.

A) $\text { E4 }$
B)Sa
C)SBb
D)SBV
E) $\mathrm { B } 2 \mathrm {~S}$

Question 39

Which of the following is NOT one of Hubble's types of galaxies?

A)normal spirals
B)barred spirals
C)Seyfert spirals
D)irregular type II
E)dwarf ellipticals

Question 40

You observe a spiral galaxy with a large central bulge and tightly wrapped arms. It would beclassified an:

A)Sc.
B)Sb.
C)Sa.
D)SO.
E)E7.

Question 41

What is the nearest huge cluster of thousands of galaxies, to which the Local Group maybelong?

A)The Great Wall
B)Coma Cluster
C)Virgo Cluster
D)Corona Borealis Cluster
E)Sagittarius Cluster

Question 42

Why do some quasars have redshifts greater than 1?

A)They are made of different elements than any other objects in the universe.
B)They are very distant, with relativistic redshifts that take into account dilation of space-time,as Einstein predicted.
C)They are made of tachyons and thus are able to move away from us faster than the speed oflight.
D)Einstein proved it is impossible to have a redshift greater than 1; these are all due togravitational lensing tricking us.
E)They are moving towards us, which throws off our spectrometers.

Question 43

A supernova that occurred 30,000 years ago in a galaxy 100,000 light-years away will beobserved on Earth:

A)30,000 years from now.
B)70,000 years ago.
C)70,000 years from now.
D)100,000 years ago.
E)100,000 years from now.

Question 44

According to the Tully-Fisher relation, the rotational speed of a spiral galaxy, as indicated bythe broadening of spectral lines, allows us to determine the galaxy's

A)luminosity.
B)color.
C)redshift.
D)mass.
E)shape.

Question 45

According to the Hubble Law, a galaxy with a velocity of 25,000 km/s will be:

A)100 million pcs away.
B)400 million pcs away.
C)700 million pcs away.
D)1000 million pcs away.
E)less than 1 million pcs away.

Question 46

Quasars usually have their distances measured by what technique?

A)Type II supernovae
B)Cepheids
C)Parallax
D)Hubble's Law
E)Tully-Fisher relation

Question 47

The look-back time of an object is directly related to its:

A)mass.
B)distance.
C)luminosity.
D)size.
E)composition.

Question 48

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

A)a sudden surge of star formation.
B)a series of supernovae around the core.
C)the sudden collapse of the core into a supermassive black hole.
D)a close encounter with a neighbor galaxy.
E)the fusion of helium into carbon in their cores.

Question 49

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

A)moving away from us.
B)moving towards us.
C)expanding explosively.
D)blueshifted.
E)not forming new stars.

Question 50

Which of the following paraphrases Hubble's Law?

A)The faster the galaxy spins, the more massive and luminous it is.
B)The greater the distance to a galaxy, the greater its redshift.
C)The greater the distance to a galaxy, the fainter it is.
D)The more distant a galaxy is, the younger it appears.
E)The older the galaxy appears to us, the more luminous it is.

Question 51

Most galaxies in the Local Group are:

A)dwarf spirals.
B)small irregulars similar to the Magellanic Clouds.
C)larger spirals than either the Milky Way or M-31 in Andromeda.
D)dwarf ellipticals, similar to the companions of M-31.
E)brown dwarfs, with even more dust than our own Galaxy.

Question 52

For finding the distance to M31, Hubble relied upon:

A)RR Lyrae stars in its globular clusters.
B)type I supernova in its core.
C)type II supernova in its spiral arms.
D)Cepheid variables in its spiral arms.
E)planetary nebulae near its core.

Question 53

How does the modern value of Hubble's constant compare to Hubble's original publishedvalue?

A)They are very similar.
B)The modern value is about 7 times lower than the original value.
C)The modern value is about 7 times higher than the original value.
D)The modern value is about 700 times lower than the original value.
E)The modern value is about 700 times higher than the original value.

Question 54

That quasars were at cosmological distances yet appeared like ordinary faint stars meant:

A)they were the brightest stars ever observed.
B)they must be very large.
C)they must contain many O and B type stars.
D)they must be producing such large quantities of energy than even fusion could not explaintheir output.
E)they must be very small, but bright due to gravitational lensing.

Question 55

Which statement about the Local Group is FALSE?

A)It contains about 45 member galaxies.
B)Its notable spirals include the Milky Way, M31, and M33.
C)Most of its members are dwarf elliptical and irregular galaxies.
D)It contains the large radio galaxy Centaurus A.
E)It is about three million light-years across.

Question 56

According to Hubble's Law, the greater a galaxy's redshift, the:

A)closer it is to us.
B)younger it is.
C)faster it's approaching us.
D)farther it is from us.
E)greater its mass.

Question 57

Why does the Cepheid "standard candle" have limited usefulness beyond 20 Mpc?

A)Distant galaxies are seen in the past, when Cepheid variables behaved differently than they dotoday.
B)Distant galaxies are so young they do not contain Cepheids.
C)Cepheids are too faint to be seen beyond that distance, even with HST.
D)The light variability of Cepheids diminishes with distance so they do not appear to vary there.
E)Older distant Cepheids are of Population II, where the period-luminosity relation no longerworks.

Question 58

What is true of spiral galaxies?

A)They are much less common at larger redshifts.
B)They are relatively rare in regions of high galaxy density.
C)They are only found in the center of rich galaxy clusters.
D)They have never been seen to have large redshifts.
E)They evolve from giant ellipticals.

Question 59

A quasar's spectral lines are:

A)emission lines with large redshifts.
B)a continuum from the synchrotron radiation.
C)fuzzy absorption lines from the merged light of the billions of stars.
D)too complex for any interpretation.
E)nonexistent, the gas so hot as to be totally ionized, so no lines are seen.

Question 60

The Tully-Fisher relation exists between the galaxy's luminosity and its:

A)color.
B)age.
C)rotation.
D)mass.
E)size.

Question 61

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

A)20 A.U.
B)15 parsecs.
C)150 kilometers.
D)3 kpc.
E)two million light-years.

Question 62

The lobes of a radio galaxy can be as much as:

A)dozens of light-years from the galaxy's nucleus.
B)hundreds of light-years from the galaxy's nucleus.
C)thousands of light-years from the galaxy's nucleus.
D)millions of light-years from the galaxy's nucleus.
E)billions of light-years from the galaxy's nucleus.

Question 63

Most active galactic nuclei are powered by:

A)supermassive black holes.
B)a large number of supernovae.
C)mergers of compact objects.
D)black hole mergers.
E)extra-terrestrial civilizations.

Question 64

________ galaxies are essentially featureless; their light reveals evidence for the presence ofonly old red Main Sequence and red giant stars.

Question 65

Hubble's Law starts as a plot of recessional ________ versus distance to the galaxies.

Question 66

In color photos, spirals typically have ________ arms with pink H II regions.

Question 67

A galaxy that was once a quasar is likely to:

A)have burned all its fuel by now and be dark.
B)now be a dwarf irregular.
C)have a black hole at its nucleus.
D)still be a quasar.
E)be less than 5 billion years old.

Question 68

Which of the following does the intensity of synchrotron radiation NOT depend on?

A)mass of the electron
B)temperature
C)speed of electrons
D)frequency of radiation
E)strength of the magnetic field

Question 69

What is true of the lobes of a radio galaxy?

A)They are perpendicular to the galactic plane.
B)They are hotter than the galactic core.
C)They radiate primarily in the X-ray.
D)They extend out along the galactic plane.
E)They form close to the edge of the galaxy.

Question 70

Synchrotron radiation produces a(n)________ spectrum.

A)continuous nonthermal
B)emission line
C)absorption line
D)continuous, with some emission lines
E)continuous, with some absorption lines

Question 71

The magnetic fields carried by jets coming from active galactic nuclei are generated by:

A)the combined magnetic fields of the many stars near the galaxy's center.
B)the central black hole.
C)the movement of the interstellar matter of the galaxy.
D)the movement of the stars in the galaxy.
E)charged matter in the accretion disk of the central black hole.

Question 72

Although theory says a massive black hole with an accretion disk should be emitting X-rays,many black holes emit:

A)mostly in the infrared.
B)only in the visible.
C)mainly in the gamma.
D)virtually no radiation at all.
E)equally across the entire electromagnetic spectrum.

Question 73

The huge lobe radio galaxy at the center of the Virgo Supercluster is:

A)Virgo X-1.
B)M-87, a giant elliptical galaxy.
C)M-74, a very bright Seyfert Spiral.
D)M-82, disturbed by the passage of M-81 nearby.
E)the Large Magellanic Cloud, disturbed by Supernova 1987A.

Question 74

If we are directly in the line of a jet coming out of the lobe galaxy's core, we see a:

A)hypernovae.
B)pulsar.
C)quasar.
D)blazar.
E)magnetar.

Question 75

Why is the energy source for active nuclei like Seyferts thought to be compact?

A)The sources appear to be single stars in photos.
B)Their energy appears to be non-stellar synchrotron radiation.
C)The light can vary over short time intervals.
D)We know the masses of the black holes that lurk there, and can find their radii.
E)They are all strong radio sources, with assigned frequencies by their sizes.

Question 76

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

Question 77

The quasars with the largest presently known redshifts are close to:

A).96.
B)3.
C)8.
D)20.
E)65.

Question 78

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

A)one solar mass a century.
B)one solar mass a decade.
C)one solar mass a year.
D)ten solar masses a year.
E)one solar mass a day.

Question 79

In what sense are the quasars "quasi-stellar"?

A)Their energy production is hydrogen-helium fusion, like main sequence stars.
B)They are upscale versions of O stars, yet hundreds of times more massive.
C)Their luminosity comes from the millions of supergiants that compose them.
D)Their spectra are like that of ordinary stars.
E)In short time exposures, their images looked stellar.

Question 80

The type of radiation coming from active nuclei due to electrons spiraling in very strongmagnetic fields at relativistic speeds is:

A)positron radiation.
B)thermal energy.
C)a blackbody curve.
D)synchrotron radiation.
E)nuclear energy.