My undergraduate research focused on understanding the nature of the broad-line region in active galactic nuclei (AGNs). The proximity of the broad-line region to the central black hole makes it an important probe of the physical conditions in the center of active galaxies. My honors thesis centered on the discovery of an intrinsic Baldwin Effect in the H&beta broad emission line in the active galaxy NGC 5548. This inverse, non-linear correlation between the equivalent width of the H&beta line and the continuum flux provides a constraint on photo-ionization models of the broad-line region. I also investigated different cross-correlation techniques for determining the time delay between changes in the continuum and broad emission lines. This time delay provides information on the size and structure of the broad-line region.

Related Publications

"An Intrinsic Baldwin Effect in the H&beta Broad Emission Line in the Spectrum of NGC 5548." Karoline M. Gilbert & Bradley M. Peterson, 2003, ApJ 587, 123

"Central Masses and Broad-Line Region Sizes of Active Galactic Nuclei. II. A Homogeneous Analysis of a Large Reverberation-Mapping Database." Peterson, B. M., Ferrarese, L., Gilbert, K. M. , Kaspi, S., Malkan, M. A., Maoz, D., Merritt, D., Netzer, H., Onken, C. A., Pogge, R. W., Vestergaard, M., Wandel, A. 2004, ApJ, 613, 682

I also reduced some data for the OSU Spiral Galaxy Survey:

"Near-Infrared and Optical Morphology of Spiral Galaxies." Paul B. Eskridge, Jay A. Frogel, Richard W. Pogge, Alice C. Quillen, Andreas A. Berlind, Roger L. Davies, D.L. DePoy, Karoline M. Gilbert, Mark L. Houdashelt, Leslie E. Kuchinski, Solange V. Ramirez, K. Sellgren, Amelia Stutz, Donald M. Terndrup, Glenn P. Tiede, 2002, ApJS 143, 73