Review Questions

1. What is the definition of epsilon, the radiative efficiency for black hole accretion?  What does all the accreting mass energy convert into if epsilon = 1? What does all the accreting mass energy convert into if epsilon = 0? Is the rate at which the black hole mass grows faster or slower if the radiative efficiency is smaller? Explain your answer.

2. What is the Eddington luminosity, LEdd? What is the bolometric luminosity, Lbol? What is the Eddington ratio, λEdd , in terms of these two quantities?  Explain why the Eddington ratio is also proportional to the specific black hole mass growth rate, (dMBH/dt)/MBH?

3. Describe at least two methods for observationally measuring black hole masses in AGN/quasars.

4. Consider the Eddington Ratio Distribution Functions (ERDFs) presented in Figure 18.3. In this study, what is a Type 1 quasar and what is a Type 2 quasar?  Compare and contrast the population fractions and HI column densities of Type I and Type 2 quasars for log(λEdd)  ≤ -1.7 and for log(λEdd)  > -1.7.  

5. Compare and contrast the four main theoretical hypotheses (thermal, cosmic ray, Compton, radiative) for the physical mechanism driving high-velocity quasar winds.

6. What are some compelling reasons that the winds are radiative line-driven? What is the line-force multiplier and what are the physical conditions that make it larger versus the conditions that make it smaller?

7. Consider Figure 18.6. Briefly explain what this diagram is saying about the physics of accreting black holes and their winds.

8. Consider Figure 18.7, the "Boroson Diagram." Briefly explain what this diagram is saying about accreting black holes, their host galaxies, and the evolution of this relationship?

Problems

1. Under construction