My research focuses on discovering the nature of the dark energy currently accelerating the expansion rate of the Universe. I use the tools of observational astronomy to address this question of fundamental physics. The currently most successful probe of the kinematics of the Universe over the past 10 billion years has involved the use of Type Ia supernovae (SNeIa) to measure the evolution of luminosity distance vs. redshift (Riess98, Perlmutter99). I am currently planning for using the ~100,000 SNeIa that will be observed by the Large Synoptic Survey Telescope (LSST) to constrain the nature of dark energy through measurements of the equation-of-state parameter of the dark energy, w=P/rho. This is a field where the observations are clearly far out in front of theory and thus call for investigation by multiple pathways to confirm the observational results and explore new areas to provide further guidance for the hope of an eventually theoretical explanation for dark energy that quantitative predicts its observed behavior today.
From 2012-2015 I served as the Scientific Spokesperson for SDSS-III, which was a 6-year project that surveyed millions of galaxies, hundreds of thousands of quasars, and opened new vistas within our Milky Way.
I have previously been involved in Pan-STARRS-1 survey telescope in Hawai'i. This project has discovered thousands of supernovae and other interesting transient events over a 3-year survey. A public data release is planned for 2016.
Members of my research group study advanced statistical techniques to optimally extract information from SNIa surveys (Anja Weyant; PhD 2014), as well as the origin of elements and galaxy evolution through studies of metal-line absorption systems backlit by distant quasars (Shailendra Vikas; PhD 2013) as part of the SDSS-III BOSS project). I am currently leading a 3-year NOAO Survey project, SweetSpot, with a goal of observing ~150 SNeIa in the near-infrared in the nearby Hubble flow (0.02
My masters student Melanie Good (MS 2011) started an exoplanet transit search group, Survey of Transiting Extrasolar Planets at the University of Pittsburgh (STEPUP), to study planets around other stars and, in particular, complement the radial-velocity searches of the SDSS-III MARVELS project. STEPUP has been active for the past five years and has involved more than 30 Pitt undergraduate students in active research and collaboration with international teams of astronomers.
The general technical theme of my research work is moving into the next generation of time-domain astronomy where we will be analyzing large data sets using sophisticated databases and to ask new kinds of questions as we continue our exploration of the Universe.