The members of the Astronomy and Astrophysics group are among the leaders of their chosen areas of research. We are one of the largest astrophysics groups within a physics department in the country. The research conducted in our group is interwoven and dynamic, with six complementary focus areas.
Supernovae are the explosions of dying stars. But in their death they give clues to the size and fate of the universe.
Our group is among the top few internationally in supernova research. Baron and Kilic are interested in the systematics of how supernovae explode and what kinds of stars lead to different supernovae. Baron studies the spectra of the expanding supernova atmosphere to determine physical conditions and chemical abundances in the ejecta. Kilic observes compact binary star systems that may lead to supernovae explosions. Some of these binary systems are among the strongest gravitational wave sources known. Dai studies the populations of gamma-ray bursts and their jet breaks. We have set up a "supernova spectrum repository" - a Web site at which any astronomer can view all of the supernova spectra that we gather from observers. This makes us the "headquarters" of supernova spectra.
Cosmological research in our group is anchored in observational data and aims at gaining a deep understanding of our universe.
Galaxy HUDF-JD2 From the Hubble Ultra Deep Field. Source: Hubblesite.org
Wang's research focuses on using cosmic microwave background anisotropy, galaxy redshift surveys and supernovae to determine the cosmological parameters that describe our universe, to probe the physics of the very early universe, and to study the dark energy in the universe. Wang is a member of the Euclid Consortium, a Medium-class mission approved by the European Space Agency. Dai uses galaxy clusters to study the distribution of dark matter, the baryon fraction in clusters, and dark energy. Baron studies the use of supernovae as distance indicators to remote galaxies to determine the age, size and fate of the universe. Wang and Baron study the systematic uncertainties of using supernovae as cosmological probes.
Extragalactic astronomy focuses on the chemical and dynamical evolution on a vast scale.
Dai and Leighly study Active Galactic Nuclei. The ultimate power source for Active Galactic Nuclei is thought to be accretion onto a supermassive blackhole. Their extensive program involves observations in the X-ray, optical, and infrared, and also theoretical modeling. Leighly studies the fundamental properties (covering fractions and column densities) of quasar outflows. Dai uses gravitational lensing to map the quasar accretion disk structure. Henry studies the distribution of chemical elements in spiral galaxies like the Milky Way in order to study their origin and evolution.
Extrasolar planets and circumstellar disks are studied by two of our faculty.
Nucleosynthesis occurs through out a star's life as well as in its death. It is the key to understanding stellar evolution.
Henry studies the chemical abundances of a variety of emission line objects with the goal of understanding stellar production rates and subsequent cosmic accumulation of elements such as C, N, O, Ne, S, and Ar. Kilic studies the chemical composition of Earth-like planets around evolved stars by observing the remnants of such planets, debris disks. Kilic uses white dwarf cosmochronology to measure the ages of the oldest stars in the Galactic disk and halo and to set limits on the age of the universe.
Observational astronomy is the solid foundation that supports all of our research.
Our astronomers use ground- and space- based observatories to study supernovae, supernoave progenitors and remnants, Active Galactic Nuclei, galaxy clusters, gravitational wave sources, extrasolar planets, and debris disks. Our group has recently been awarded observing time on the ground-based MDM 2.4m, NASA IRTF 3m, APO 3.5m, KPNO 4m, Hale 5m, MMT 6.5m, Gemini 8m, Subaru 8.2m, Keck 10m, GTC 10.4m, LBT 12m telescopes and the space-based Hubble Space Telescope, Spitzer Space Telescope, XMM-Newton, and the Chandra X-ray Observatory. We use our 16-inch campus telescope for student training and weekly public star parties. Our graduate students host these star parties as well as a weekly journal club.
Computational physics studies on our 112 node Xserve cluster, at OU's OSCER super computer, at Argonne National Laboratory, at the National Energy Research Supercomputer Center (NERSC) in Berkeley are also ongoing in the areas of supernovae, cosmology, Galactic chemical evolution, active galactic nuclei, and nucleosynthesis.
Astronomy continues to be an exciting field with new ideas and new facilities emerging in the coming decade. We welcome the chance to work with motivated and qualified graduate students.