Jonathan Jerke

The Palomar-QUEST Variability Survey has been completed. This thesis has analyzed the data set with the goal of determining the variability of a large sample of quasars.

We construct light curves for each individual quasar. We interpret the light curves in terms of a structure function analysis. A slope is extracted from the scaling of the structure function to measure the power law of the quasar optical variability, taking the power spectral density to behave as a power law of the frequency of variation, f^−α. Monte carlo simulations are used to estimate the errors on the model and the final data quality. With these estimates, individual quasars are assigned a χ² value and nearly every event has a reduced χ ² less than 10. The first 100 light curves and structure functions with errors are shown in the Appendix.

We have shown that the final distribution of power law coefficients α of 1944 quasars is inconsistent with a model with a simple value of α. Several models with different α are required to explain the behavior of the sample.

We find that quasars are less variable on all time scales for increasing luminosity. We also find that the quasars with black hole masses below 10 ⁸ show a lower power law then the average. This means less massive quasars are less variable at long time scales.