Cosmology

How did our Universe begin? How did our Universe evolve into the current state? What will be the fate of the Universe?
What is dark energy? How does it evolve? Is the Cosmological Constant an accurate model for dark energy?
What is dark matter? How does it affect large-scale structure formation?
Are there systematic errors in the extragalactic distance scale and the Hubble Constant?
What is the expansion history of the universe?
How did the first galaxies and quasars form and evolve? What are the observational signatures of these first luminous objects?
How did the stars and galaxies we know today arise from the initial conditions of the Big Bang, and how did the process of Cosmic Reionization unfold?
What are the properties of the supermassive black holes that power the most distant quasars? How did they form at the cosmic dawn?
What is the relationships between supermassive black holes and host galaxies?

Don Schneider played a leading role in the development of the Sloan Digital Sky Survey Catalog, which contains over 105,000 spectroscopically-confirmed quasars found during the first two phases of the Sloan Digital Sky Survey (1999-2008).
Yuexing Li has pioneered the numerical modeling of the formation, evolution, and multi-band properties of the most distant galaxies and quasars by combining multi-scale cosmological simulations with multi-wavelength radiative transfer calculations. She has developed essential models of quasar formation, as well as a comprehensive radiative transfer code ART² ,which has a wide range of applications in modeling both continuum and emission lines from galaxies and quasars.
Derek Fox and collaborators discovered the most distant gamma-ray burst at redshift z=8.2, when the Universe was only a few hundred million years old.
Robin Ciardullo pioneered the technique of using the Planetary Nebulae Luminosity Function for extragalactic distance measurements, which is only method that can be applied to all large galaxies within ~ 20 Mpc, regardless of Hubble type or stellar population.

The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) will measure dark energy between 1.9<z
Yuexing Li is conducting computational work to investigate the formation of the first quasars, accretion onto black holes, Lyman-alpha emission from high-redshift galaxies, fossils of the first black holes and galaxies in the Milky Way, and large-scale structure formation.
Don Schneider uses data gathered by the Sloan Digitial Sky Survey, the Chandra satellite, and the Hobby-Eberly Telescope to investigate the properties of active galactic nuclei and the large-scale properties of the universe.