Date of Graduation


Document Type


Degree Name

Master of Science in Physics (MS)

Degree Level





Julia Kennefick

Committee Member

Daniel Kennefick

Second Committee Member

William Oliver

Third Committee Member

Mark Arnold


Pure sciences, Black holes, Quasars


The goal of this thesis is to present an approach to understanding the dynamics that govern the evolution of active galactic nuclei (AGN) in general, and those associated with spiral galaxies in particular. This approach starts with the continuity equation governing the mass function for a population of supermassive black holes (SMBHs). This approach is then extended to the luminosity function for AGN. Where the dynamical parameters that govern accretion are fairly well known, those values are adopted. The values that are not as well known are constrained by comparing evolved luminosity functions with observed luminosity functions. Boundary conditions for this model are typically taken to be locally observed mass functions unless otherwise specified.

It can be concluded that the Eddington ratio is likely a function of time and possibly a function of mass. The duty cycle is likely a function of both time and mass. The qualitative evolution of the Eddington ratio and duty cycle can be inferred from the luminosity evolution and density evolution of observed luminosity functions respectively. Additionally, models with a break in the duty cycle agree well with observations. This may be an indication of feedback within the host galaxy. The effect of mergers is also examined briefly, and the results imply lower Eddington ratios than models without mergers.

smbh-evol.nb (169 kB)