I am now working at the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU). My new home page can be found here.
I currently serve as the software lead for the Palomar Transient Factory (PTF), a project to systematically map out the time variable sky. I lead PTF's luminous supernova program, and I have already submitted the projects first science paper from our initial discoveries. My dissertation work at the University of Texas uncovered a new population of luminous supernova (events having peak luminosities 10 to 100 times brighter than typical supernovae). The most famous of these, SN 2006gy, has been studied by research teams around the world and was honored by Time Magazine as the #3 discovery of 2007.
Luminous Supernovae may be divided into two groups on observational grounds: events with prominent narrow emission lines in their spectra (LSN-IIn) and those without (LSN-Ic; see the spectra shown above). It is believed that LSN-IIn represent explosions of massive stars surrounded by dense, hydrogen rich circumstellar media (CSM). As the supernova blast wave interacts with the CSM, the (large) kinetic energy is efficiently converted into light, and this results in a luminous display. The luminous supernovae lacking hydrogen are perhaps more puzzling. These events show high expansion velocities (>10,000 km/s), yet they cool rather slowly. This suggests physically large progenitor systems--too large in fact to be explained by any bound, hydrogen deficient star. It appears that something happened to the system to eject a massive shell prior to the final injection of energy. I am currently working to unravel the physical origin of luminous supernovae and to build the sample of local events with an eye toward future discoveries in early universe.
Host Galaxy properties offer significant clues to the physical makeup of supernova progenitors. With this in mind, I am working to discover the host galaxy environments favored by the various flavors of supernovae. Using a spectroscopically complete sample of supernovae identified without bias to type or host galaxy, I am identifying the environments most conducive to the production of both normal and peculiar supernovae.