Galaxy_Classification_Compiled_Q

Center for Astronomy Education University of Arizona Astronomy Assessment and TPS Questions: Galaxy Classification 1. Why are the spiral arms of spiral galaxies typically blue in color? a. They are usually moving toward us and are Doppler shifted to blue wavelengths. b. The gas and dust in the arms filter out all but the blue light from stars in the arms. c. Stars are forming in the spiral arms so there are many more high mass, hot, blue stars. d. Almost all the stars of the disk are in the arms of the galaxy and their light makes it appear blue. ----------------------------------------------------------------------------------------------------------------- Use the three images of galaxies shown at right ( A , B , and C ) to answer the following three questions 2. In which of the galaxies would you expect to see many bright blue stars (choose all that apply)? 3. In which of the galaxies would you expect to see mostly red stars (choose all that apply)? 4. In which of the galaxies would you expect to see regions of abundant gas and dust (choose all that apply)? ----------------------------------------------------------------------------------------------------------------- A B C

Center for Astronomy Education University of Arizona 5. In how many of the three galaxies shown below would you expect to see regions of abundant gas and dust? a. only one b. two c. all three d. none ----------------------------------------------------------------------------------------------------------------- Use the two images of galaxies shown below ( A and B ) to answer the following two questions. 6. In which of the galaxies would you expect to see many bright blue stars? a. Only galaxy A b. Only galaxy B c. Both galaxies A and B d. Neither galaxy A or B 7. In which one of the galaxies would you expect to see mostly red stars? a. Only galaxy A b. Only galaxy B c. Both galaxies A and B d. Neither galaxy A or B ----------------------------------------------------------------------------------------------------------------- Galaxy A Galaxy B

Center for Astronomy Education University of Arizona Use the images below to answer the following three questions 12. Using the images above, which of the galaxies has/have only old stars? a. A b. B c. C d. Only B & C e. All of the galaxies 13. Using the images above, which of the galaxies has/have lots of gas and dust? a. A b. B c. C d. Only A & C e. All of the galaxies ----------------------------------------------------------------------------------------------------------------- Use the images below to answer the following three questions A B C 14. How many of the galaxies shown above would you expect to have an abundant amount of gas and dust? a. Only one A B C Commented [m2]: Sentence added Commented [m3]: Sentence added

Center for Astronomy Education University of Arizona b. Two c. All three 15. In how many of the galaxies shown above would you expect stars to be forming? a. Only one b. Two c. All three 16. How many of the galaxies shown above would you expect to contain many O-type stars? a. Only one b. Two c. All three ----------------------------------------------------------------------------------------------------------------- 17. How would you expect the luminosity of a spiral galaxy to compare to the luminosity of an elliptical galaxy if they have the same number of stars? a. The elliptical galaxy would be more luminous. b. The spiral galaxy would be more luminous. c. They would have the same luminosity. 18. What are the “dark” regions in the disks of spiral galaxies? a. Places where there are no stars b. Places where the stars do not give off visible light c. Places where there is an abundance of black holes d. Places where stars are currently forming A B C ----------------------------------------------------------------------------------------------------------------- Use the images above ??? and spectral curve below ????to answer the following two questions Energy Commented [m4]: Sentence added . I geth the spectral curves, but what other images???

Center for Astronomy Education University of Arizona 22. Use the picture above to answer this question. If in ten million years the galaxy shown above collides with a spiral galaxy, what could occur? a. Only an elliptical galaxy could form b. Only a spiral galaxy could form c. Either an elliptical or a spiral galaxy could form d. No new galaxy could form ----------------------------------------------------------------------------------------------------------------- ----------------------------------------------------------------------------------------------------------------- Use the images below to answer the following three questions A B C Commented [m5]: Sentence added

Center for Astronomy Education University of Arizona 23. Which of the galaxies shown above would be the result of an elliptical galaxy colliding with another elliptical galaxy? a. A b. B c. C d. A or C e. All three 24. Use the three pictures above to answer. Which of the following is possible? a. The collision of Galaxy A and Galaxy B can produce Galaxy C . b. The collision of Galaxy A and Galaxy C can produce Galaxy B . c. The collision of Galaxy B and Galaxy C can produce Galaxy A . d. All of the above e. None of the above 25. Use the image above to answer this question. Which of the following must be false about the galaxy shown? a. It contains old stars. b. It has active star formation. c. It formed from the collision of two elliptical galaxies. d. It contains red stars. e. None of the above ----------------------------------------------------------------------------------------------------------------- 26. Which of the following is true of red giants? a. They live much longer than main sequence stars. b. They contribute the majority of red light responsible for giving elliptical galaxies a reddish color. c. They are a relatively short phase within the life of a star. d. They are too dim to contribute much to the reddish color of elliptical galaxies. e. None of the above 27. How do you know the red light coming from elliptical galaxies cannot be mainly from red giants? a. Red giants are not very luminous. b. Red giants are too big to be the dominant star of the galaxy. c. Because the red giant phase is very short, there are fewer red giants than other types of stars. d. Most of the stars that exist over the lifetime of an elliptical galaxy never become red giants. e. None of the above Commented [m6]: Image enlarged and placed at the right