Astrophysics/Astronomy

Here at the University of Cincinnati, research in astrophysics can be broadly characterized as the investigation of young stellar systems and their environment, primarily at infrared wavelengths, and the study of stellar populations. Stars are born deeply embedded inside massive clouds of gas and dust. The dust not only dims the light from these stars, but the energy the dust absorb causes it to glow. Because the dust is much less efficient at obscuring the intrinsic light from such stars at infrared wavelengths than in the visible or ultraviolet, and because most of the dust-glow also occurs in the infrared, this spectral region is a prime window through which the formation and evolution of young stellar systems can be investigated. We have also developed powerful new tools for the investigation of the integrated light of star clusters and galaxies, and use these to understand the formation and evolution of stellar systems that are too distant to resolve the light of the individual stars.

Dr. Matthew Bayliss works on a variety of problems in observational astrophysics and cosmology involving galaxy clusters, the first generation of galaxies, and gravitational lensing. Galaxy clusters are the largest structures in the universe and contain on the order of 1000 individual galaxies bound within a common gravitational potential well. Galaxy clusters contain sufficiently large concentrations of mass that they often produce dramatic gravitational lensing effects in which the galaxy cluster mass distribution acts as a natural magnifying glass that bends light from distant background sources. He uses galaxy cluster gravitational lensing phenomena to study both the (foreground) galaxy cluster lenses, as well as the magnified distant (background) sources. Dr. Bayliss is an observer/experimentalist and uses a wide range of facilities in my research, including orbital NASA observatories like the Hubble Space Telescope, the James Webb Space Telescope, and the Chandra X-ray Observatory. I also make frequent use of large ground-based observatories, including the Magellan and Gemini telescopes.

Dr. Colin Bischoff studies the polarization of the Cosmic Microwave Background (CMB) using the BICEP series of telescopes at the South Pole. The CMB is a relic radiation field that was emitted shortly after the Big Bang. By studying CMB polarization, he hopes to detect a signal of primordial gravitational waves that are predicted by inflation, our leading theory of the conditions that produced the Big Bang. Two currently operating telescopes, BICEP3 and the Keck Array, are currently producing the most sensitive CMB polarization data for this purpose. Dr. Bischoff’s efforts span instrumentation, telescope operations, and data analysis, with special focus on polarized microwave foregrounds from the Milky Way, which can bias our measurements of the primordial signal. He is also involved in planning for the future BICEP Array and CMB Stage 4 experiments.

Dr. Michael Sitko's (Emeritus) work deals primarily with the physical and chemical evolution of the material in protostellar disks using infrared spectroscopy. These disks of gas and dust are the material from which planetary systems form. By combining infrared spectroscopy with high spatial resolution imaging and interferometry observations, the structure, dynamics, and chemical content of planet-building disks systems are determined. It is thought that these systems formed in much the same way as our own solar system. In order to investigate this connection, Sitko is also involved in the investigation of comets, the most pristine remnants of the early solar system. The telescopes used for this work include NASA's Infrared Telescope Facility, the Subaru telescope, and the Keck telescopes in Hawaii, the ESO Very Large Telescope in Chile, The Gemini telescopes in Hawaii and Chile, and the Hubble and Spitzer Space Telescopes.