Exam 23: Galaxies

For galaxies in the Hydra cluster, the recessional velocity is 61,000 km/sec. Assuming the nonrelativistic solution, what is the shift in frequency for the Balmer H $\alpha$ line, the rest wavelength of which is 656.3 nm?

Approximately how many galaxies are included in the collection known as the Local Group of galaxies?

Why are the gravitational lens image arcs of a distant galaxy photographed around the center of a cluster of galaxies significantly more blue in color than the cluster galaxies themselves?

Voids are believed to contain:

It is proposed that the ordinary matter and the dark matter in the galaxy cluster 1E0657-56 have become separated. This is based on the assumption that:

One astronomer (astronomer A) claims that the Hubble constant is 84 km/s/Mpc, while another (astronomer B) claims that it is 63 km/s/Mpc. If, based on the Hubble constant, astronomer A claims that a particular galaxy is 3.00 billion ly away, then astronomer B would claim that it is:

A standard candle is an object with a known luminosity, or, equivalently, a known absolute magnitude. To obtain the distance to the object one still has to use:

The type or group of galaxies that contains both the largest and smallest galaxies in the universe is the:

It is the year 1920 and you are conducting a survey of the astronomy community on the question: "What is the nature of the spiral nebulae?" What response are you likely to receive?

Which of the following would you NOT be as likely to find in the central bulge of a spiral galaxy?

The Milky Way Galaxy:

If the estimated distance from Earth to the Coma Cluster of galaxies is about 300 million ly (see Figure 23-21 of Universe, 11th ed.(in the text)), what is its velocity of recession?

If the elliptical galaxy in Hydra, whose image and spectrum are shown at the bottom of Figure 23-16 (Universe, 11th ed.), were to be at a distance of 3 billion ly, what would be the value of the Hubble constant H₀? (Be careful with units.)

What do we know about the direction in which spiral galaxies rotate?

Which common household phenomenon represents a close analogy to the distribution of galaxies in our universe?

Parallax and masers are two techniques for measuring distances in astronomy. Although very different from each other, they share a characteristic that is different from the other main measuring techniques. This is that:

What assignment is given to a galaxy with a large nuclear bulge and tightly wound arms starting from a bar through the central part of the galaxy?

Which of the following properties would NOT be important for a type of astronomical object being considered for use as a "standard candle" for distance estimation?

What is distinctive about the Coma Cluster of galaxies?

A Cepheid variable is observed in a galaxy 1 Mpc distant. Its apparent magnitude of 19.8 corresponds to a brightness ratio of b/b_Ÿ = 2.35 x 10^-19. What is its period?