Review Questions

1. What is "galactic conformity"? What does it tell us about the evolution of galaxies in large groups or small clusters?

2. What is the "conditional luminosity function" (CLF) and what information does it provide? What is "halo occupation distribution" (HOD) formalism and what information does it provide? 

3. Consider Figure 15.2, which shows the first moments of HOD functions. Describe what information can be gleaned from these curves.  Give a brief summary of HOD and describe how it can be applied in the context of quasar absorption line galaxy-absorber studies?

4. Let's say you build a sample galaxy-absorber pairs and wish to examine whether the CGM absorption correlates with the star formation rate in the galaxies. Why should you be concerned whether the galaxies are or are not in groups? In other words, is there a reason that, if some of your galaxies are in groups, it may be difficult to obtain an unbiased result from your investigation?

5. Consider a typical small galaxy group similar to the Local Group.  What is the intragroup medium (IGrM), as opposed to the CGM of the individual group member galaxies?  

6. What do simulations predict for the evolution of IGrM properties? Describe the changes in the IGrM from when the main galaxies are on their very first infall approach to periapsis to after their first pass and are approaching apoapsis?  Be sure to address any change(s) in the gas phases and column densities in the IGrM, any change(s) in the kinematics of the bridge relative to the group barycenter, and any change(s) in the CGM of the individua galaxies.

7. Consider a cluster of galaxies. What is the intracluster medium (ICM)? Why does the ICM generate a smooth, bright, X-ray profile?

8. What is the β-model? Describe its underlying assumptions about the ICM. Describe what Figure 15.9 is showing us about the ICM.

9. Describe the theoretical ideas that are invoked to understand the relatively high metallicity, quasi-solar abundance pattern of the ICM, and the lack of a metallicity gradient outside the cluster core (why are the metals so well mixed in the outer regions of the clusters?) .

Problems

1. Under construction