Supernovae, cosmology, and the mysterious dark energy.
I am primarily concerned with clues to the nature of supernova progenitors through bulk analyses; rates, environmental effects (star-formation, metallicity, etc.), and the global evolution of these properties over the history of the Universe.
Black Americans, Hispanic Americans, and Native Americans are seriously underrepresented relative to their respective numbers in the U.S. population in the fields of astronomy, space science, and physics.
I am involved with a number of initiatives addressing underrepresented minorities in astronomy and physics, and looking at approaches to improve recruitemnt and retention.
Stuff I do when I'm not in the office...
We're running program to locate distant supernovae in and around the target clusters of the HST Frontier Fields Survey. Our goals have been to improve the constraints on Type Ia supernova rates at z > 1.5, and to refine cluster mass models by probing line-of-sight cluster lensing magnification of background supernovae. Along the way we've found some very interesting supernovae, including "Refsdal" (shown above). The light from this unique event has been bent by gravity around the forground galaxy, resulting in four images of the same event, which can be seen in the yellowish knots in the ring around the yellow galaxy above the bright star at the bottom of the image.
The Hubble Space Telescope has been in orbit for over 25 years, and in that time has amassed an impressive legacy of imaging data. The HLA and HSC take this vast and diverse archive and create highly useful, science ready products.
Data Release 8 of the HLA is the first produced using AstroDrizzle and other DrizzlePac tools, providing improved WFC3 standard imaging data. Version 1 of the HSC combines tens of thousands of visit-based source-lists into a master photometry catalog. The HSC database is accessable via the MAST Discovery Portal, with data overlays and analysis tools (be sure to see the FAQs and Use Cases). A HSC CasJobs interface is also available for large and complex queries.
Here is my 2016 National Science Foundation Astronomy and Astrophysics Postdoctoral Fellows Symposium keynote talk on "The Importance of Diversity" (iCloud Keynote view only, and PDF) which I gave at the 2016 Winter AAS meeting. Included are some useful statistics on the state of the profession in physics and astronomy.
Here are some initiatives on minority participation in physics and astronomy I have been involved in: