The figure below shows the spectra of two galaxies A and B. Relative flux density 3.5 3.0 2.5 2.0 1.0 0.5 A option from mwww 4000 B 4500 5500 Wavelength (Ang.) 5000 6000 6500 7000 1. Which of these galaxies has ongoing star formation? How can you tell? 2. One of these galaxies has Hubble type E3 while the other is SBb. Which is which? What does the 3 E3 tell you about the galaxy? What does the SB in SBb tell you about the galaxy? 3. What effects would dust have on the two spectra? 4. Which galaxy would you expect to have more far-infrared emission? Explain.

The figure below shows the spectra of two galaxies A and B. Relative flux density 3.5 3.0 2.5 2.0 1.0 0.5 A option from mwww 4000 B 4500 5500 Wavelength (Ang.) 5000 6000 6500 7000 1. Which of these galaxies has ongoing star formation? How can you tell? 2. One of these galaxies has Hubble type E3 while the other is SBb. Which is which? What does the 3 E3 tell you about the galaxy? What does the SB in SBb tell you about the galaxy? 3. What effects would dust have on the two spectra? 4. Which galaxy would you expect to have more far-infrared emission? Explain.