B.A. University of Kansas (1977)
Ph.D. University of Michigan (1983)
My research focuses on the cosmic chemical evolution of elements in the first three rows of the periodic table, e.g., C, N, O, Ne, S, Cl, and Ar, by studying the interstellar medium (ISM) of galaxies over a broad redshift range. My long-term collaborators have included Bernard Pagel (Sussex, deceased), Mike Edmunds (Cardiff), Reggie Dufour (Rice, deceased), Karen Kwitter (Williams College) and Bruce Balick (U. Washington). Together we measure the interstellar abundances of these elements spectroscopically by observing ISM abundance probes such as H II regions and planetary nebulae. These are regions associated with recent star formation and star death, respectively, in which hot stars heat the surrounding low density nebulae and cause the latter to radiate in discrete emission lines. In turn, these lines are converted into elemental abundances representative of the interstellar material out of which the objects formed.
Once the abundance information becomes available, I then compute both detailed photoionization and chemical evolution models to interpret the results in a galactic context. Our studies have focused on the disks of the Milky Way and M31 galaxies. Our data were obtained during observing runs at McDonald, Gemini North, Kitt Peak, Cerro Tololo, Apache Point, Spitzer Space Telescope, and Hubble Space Telescope observatories.
PhD Students: James Buell (Alfred State University of New York), Tad Thurston (OCCC), Joe Howard (Salisbury State University), Jackie Milingo (Gettysburg College), Aida Nava Wofford (UNAMexico Ensenada), Timothy Miller (OU)
