Exam 19: Galaxies

If you found a galaxy with an H $\alpha$ emission line that had a wavelength of 756.3 nm, what would be the galaxy's redshift? (Note that the rest wavelength of the H $\alpha$ emission line is 656.3 nm.)

(Multiple Choice)

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Question 81

Microquasars are scaled-down versions of quasars, the former being powered by accretion onto stellar-sized black holes, the material being provided by a companion star.The underlying mechanism seems to be very similar in both microquasars and their supermassive AGNs.Typical microquasars have luminosities that are ten orders of magnitude lower than ordinary quasars.What is the typical level of accretion rate in the two cases?

(Essay)

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Question 82

Type Ia supernovae have a peak luminosity of 3.7 x10³⁶ W.If you discover a Type Ia supernovae in a distant galaxy that has a measured brightness of 9.5 x10^-17 W/m², then how far away is this galaxy? Note that 1 Mpc = 3.1 x10²² m.

(Multiple Choice)

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Question 83

Quasars were first discovered in which region of the electromagnetic spectrum?

(Multiple Choice)

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Question 84

In spiral galaxies, the size of the central bulge is correlated with the

(Multiple Choice)

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Question 85

Dust in galaxies does not count as dark matter because

(Multiple Choice)

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Question 86

The nearest known quasar shows a redshift of z = 0.0516, which means it is at a distance of

(Multiple Choice)

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Question 87

For the more distant quasars, the emission lines that would normally occur in the visible domain would be shifted into

(Multiple Choice)

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Question 88

How do the current star-formation rates of spiral and elliptical galaxies compare?

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Question 89

What were the positions taken by Heber Curtis and Harlow Shapley in their "Great Debate," and how were both of them partially correct?

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Question 90

What type of galaxy is shown in the figure below?

(Multiple Choice)

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Question 91

If there is a 4 million M_SUN black hole at the center of our galaxy, why is our own galaxy not an AGN?

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Question 92

If a galaxy has a recessional velocity of 50,000 km/s, at what wavelength will you observe the H $\alpha$ emission line? (Note that the rest wavelength of the H $\alpha$ emission line is 656.3 nm.)

(Multiple Choice)

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Question 93

You see a galaxy in which the H $\alpha$ line (rest wavelength = 656.3 nm) is observed at a wavelength of 756.3 nm.What would be the observed wavelength of a particular helium line that has a rest wavelength of 1,083 nm?

(Multiple Choice)

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Question 94

The Tully-Fisher method of determination of distances to galaxies is based on the correlation between

(Multiple Choice)

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Question 95

The spectra of most galaxies tell us that

(Multiple Choice)

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Question 96

Describe the known properties of dark matter, and contrast it with "normal" matter.

(Essay)

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Question 97

How did astronomers determine that elliptical galaxies are composed mostly of dark matter?

(Multiple Choice)

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Question 98

We interpret the presence of more AGNs in the past than today to indicate that

(Multiple Choice)

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Question 99

Dark matter is most likely made up of

(Multiple Choice)

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Question 100

Showing 81 - 100 of 100

Exam 19: Galaxies

If you found a galaxy with an H α\alphaα emission line that had a wavelength of 756.3 nm, what would be the galaxy's redshift? (Note that the rest wavelength of the H α\alphaα emission line is 656.3 nm.)

Type Ia supernovae have a peak luminosity of 3.7 x1036 W.If you discover a Type Ia supernovae in a distant galaxy that has a measured brightness of 9.5 x10-17 W/m2, then how far away is this galaxy? Note that 1 Mpc = 3.1 x1022 m.

Quasars were first discovered in which region of the electromagnetic spectrum?

In spiral galaxies, the size of the central bulge is correlated with the

Dust in galaxies does not count as dark matter because

The nearest known quasar shows a redshift of z = 0.0516, which means it is at a distance of

For the more distant quasars, the emission lines that would normally occur in the visible domain would be shifted into

How do the current star-formation rates of spiral and elliptical galaxies compare?

What were the positions taken by Heber Curtis and Harlow Shapley in their "Great Debate," and how were both of them partially correct?

What type of galaxy is shown in the figure below?

If there is a 4 million MSUN black hole at the center of our galaxy, why is our own galaxy not an AGN?

If a galaxy has a recessional velocity of 50,000 km/s, at what wavelength will you observe the H α\alphaα emission line? (Note that the rest wavelength of the H α\alphaα emission line is 656.3 nm.)

You see a galaxy in which the H α\alphaα line (rest wavelength = 656.3 nm) is observed at a wavelength of 756.3 nm.What would be the observed wavelength of a particular helium line that has a rest wavelength of 1,083 nm?

The Tully-Fisher method of determination of distances to galaxies is based on the correlation between

The spectra of most galaxies tell us that

Describe the known properties of dark matter, and contrast it with "normal" matter.

How did astronomers determine that elliptical galaxies are composed mostly of dark matter?

We interpret the presence of more AGNs in the past than today to indicate that

Dark matter is most likely made up of

Thinking Like an Astronomer

Patterns in the Skymotions of Earth and the Moon

Motion of Astronomical Bodies

Gravity and Orbits

Light

The Tools of the Astronomer

The Formation of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquidthe Giant Planets

Planetary Moons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

Our Starthe Sun

The Interstellar Medium and Star Formation

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

Relativity and Black Holes

The Milky Waya Normal Spiral Galaxy

The Expanding Universe

Cosmology

Large-Scale Structure in the Universe

Life

Filters

If you found a galaxy with an H $\alpha$ emission line that had a wavelength of 756.3 nm, what would be the galaxy's redshift? (Note that the rest wavelength of the H $\alpha$ emission line is 656.3 nm.)

Type Ia supernovae have a peak luminosity of 3.7 x10³⁶ W.If you discover a Type Ia supernovae in a distant galaxy that has a measured brightness of 9.5 x10^-17 W/m², then how far away is this galaxy? Note that 1 Mpc = 3.1 x10²² m.

If there is a 4 million M_SUN black hole at the center of our galaxy, why is our own galaxy not an AGN?

If a galaxy has a recessional velocity of 50,000 km/s, at what wavelength will you observe the H $\alpha$ emission line? (Note that the rest wavelength of the H $\alpha$ emission line is 656.3 nm.)

You see a galaxy in which the H $\alpha$ line (rest wavelength = 656.3 nm) is observed at a wavelength of 756.3 nm.What would be the observed wavelength of a particular helium line that has a rest wavelength of 1,083 nm?