G_Classification_G

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???