astrophysics

The Astrophysics Group

Faculty: Balsara - BeersCrepp - Garnavich - Howk - Mathews - Rettig - Suh - Surman
Research Faculty: Bennett - Carollo - Lehner - Phillips - Placco
Professional Specialist: Davis
Emeritus Faculty: Poirier
Postdocs: Crass - Garain - Kim - Kusakabe - Yoon

Astrophysics research at Notre Dame is directed toward the study of astrophysical origins. The group's activities contribute to the Center for Astrophysics at Notre Dame University (CANDU). The center supports interdisciplinary research in three basic areas: theoretical astrophysics and cosmology, ground-based optical astronomy, and space science.

Ground-Based Astronomy

The flagship of Notre Dame's ground-based observational effort is the partnership with the Large Binocular Telescope (LBT) in Arizona. Notre Dame has joined a consortium of other universities for construction and use of this telescope. The members of this consortium are excitedly anticipating the arrival of the first light in early 2004. The LBT will be one of the most powerful and versatile telescopes in the world. It will be the premier instrument for many astronomical problems ranging from studies of the early universe to searches for planets in other star systems.

Current observational programs involve a variety of telescopes around the world including the Keck observatory in Hawaii and the Hubble Space Telescope. Ongoing research includes studies in the mysterious dark energy which is accelerating the expansion rate of the universe, studies of distant supernovae and gamma-ray bursts, studies of planet formation in young stellar systems, and studies of gravitational microlensing to search for dark matter and planets in the Galaxy.

Theoretical Research

Ongoing theoretical research includes all aspects of the origin and evolution of the universe, galaxies, stars, planets, and the interstellar medium. The astrophysics theory group has pioneered the development of modern numerical methods for hydrodynamic simulations of complex astrophysical systems. Theoretical work concerning the formation and evolution of galaxies, stars and the interstellar medium is being investigated with complex adaptive mesh magnetohydrodynamics. The group is also doing cosmological simulations of the origin and evolution of the very early universe, from the birth at the Planck scale, through inflation and various particle-physics processes, primordial nucleosynthesis, the emission of the cosmic microwave background, and the formation of large-scale structure and galaxies. These simulations are used to constrain theories for the nature of space-time and the origin of the universe. General relativistic numerical hydrodynamic simulations are also being performed as a means to understand exploding supernovae, black-hole and neutron star formation, and the formation of jets and electromagnetic bursts for accreting systems.

Another focus is theoretical nuclear astrophysics. This included nucleosynthesis in the big bang, in supermassive population III stars, during late stellar evolution (AGB stars), and explosive nucleosynthesis on accreting white dwarfs (novae), accreting neutron stars (X-ray bursts), and supernovae. The nucleosynthesis is simulated using complex nuclear reaction network models for stellar hydrostatic and/or hydrodynamic conditions. The nuclear-physics input is derived from nuclear structure and nuclear reaction models. The reaction flow is studied within the time scales of static or explosive stellar burning. Energy generation and nucleosynthesis are calculated and compared with observed luminosities and elemental abundance distributors.

Space Science

Research in space science divides into studies of cosmic-ray air showers and the development of a new Notre Dame satellite mission. In cosmic-ray research, an extensive air shower array (Project GRAND) is used to study cosmic rays and measure angles with high precision. The production mechanisms for UHE cosmic gamma rays and stellar sources such as Cygnus X-3 and Hercules X-1 are being studies along with a search for an association with gamma-ray bursts.

The group's newest endeavor is the proposed Deep Impact Microlensing Explorer Mission (DIME) in which Notre Dame's contribution will be as the Science Analysis center. Scientists at Notre Dame will utilize the onboard telescope to make parallax measurements of distant gravitational microlensing events. These observations will be crucial to characterize the nature of dark matter in the Galaxy.