The Leonard E. Parker Center for Gravitation, Cosmology and Astrophysics (CGCA) is a collaboration of world-renowned scientists working on relativistic astrophysics, numerical relativity, gravitational-wave astronomy, cosmic-ray astrophysics, cosmology, neutrino astronomy, quantum fields in curved space-time, and quantum gravity.

The Physics program at UWM, and particularly the astrophysics program, is internationally-known for its expertise and research. At CGCA, astrophysicists make novel use of observation, theory, and computation in their research. Recent major accomplishments include the discovery of one of the coolest, dimmest stellar corpses ever seen and the creation of a new NSF-funded NANOGrav Physics Frontiers Center which will continue the search for low-frequency gravitational waves.

Members of the Center play important roles in the Laser Interferometer Gravitational-wave Observatory (LIGO) Collaboration, an ambitious project to detect and study gravitational waves from astrophysical objects such as black holes and supernovae. UW-Milwaukee hosts a state of the art data center specifically designed and constructed for the analysis of data from LIGO and other astronomical observatories. The group also collaborates with the Pierre Auger Observatory which was constructed to study ultra-high-energy cosmic rays, the most energetic and rarest of particles in the universe.

CGCA is active in educational and public programming as well. An Arecibo Remote Control Center is located at UWM. Students and K-12 teachers can search for new pulsars remotely using the world's largest radio telescope in Puerto Rico. The Einstein@Home program enlists volunteers from all around the world sign up their computers to process data from gravitational wave detectors. The Center also brings in world-renowned speakers on a broad range of ongoing cosmology and gravitation research topics.