Date of Graduation


Document Type


Degree Name

Doctor of Philosophy in Physics (PhD)

Degree Level





Julia Kennefick

Committee Member

Claud H. Lacy

Second Committee Member

William Oliver III

Third Committee Member

Paul Thibado

Fourth Committee Member

Tim Kral


Active galactic nuclei, AGN feedback, AGN spectral energy distribution, galaxy evolution, spiral galaxies


I have investigated the energy output of active galactic nuclei (AGN) in order to understand how these objects evolve and the impact they may have on host galaxies. First, I looked at a sample of 96 AGN at redshifts $z \sim 2, 3,$ and $4$ which have imaging and thus luminosity measurements in the $griz$ and $JHK$ observed wavebands. For these galaxies, I have co-epochal data across those bands which accounted for variability in AGN luminosity. I used the luminosity measurements in the five bands to construct spectral energy distributions (SED) in the emitted optical-UV bands for each AGN. I compared the SED to assumptions previously made about quasars and looked for correlations between SED and other AGN and galaxy properties. Second, I used spectra of the broad line region (BLR) of Type 1 AGN to estimate the mass of the central supermassive black hole ($M_{BH}$). I found a sample of Type 1 AGN that reside in spiral galaxies in order to explore the relationship between $M_{BH}$ and pitch angle ($\phi$), a measurement of how tightly wound the spiral arms are. Type 1 AGN offer a method to estimate $M_{BH}$ at higher redshift than previous studies of the $M_{BH}$-$\phi$ relation. I was able to look at the evolution in the $M_{BH}$-$\phi$ relation which has implications for galaxy formation as well as AGN feedback.