The Texas supernova group is unique in its focus on both the observations and theory of asymmetric supernovae. They are continuing to explore Type Ia supernovae with optical and near infrared spectroscopy and optical spectropolarimetry with the goal of better understanding the progenitor evolution, the explosion physics, and the capacity of these supernovae to facilitate accurate cosmological measurements. Evidence possibly related to the binary nature of these objects has started a new branch of supernovae research to determine when the photospheres of supernovae become spherical and to better understand the dispersion in luminosity and color between objects due to effects of asphericity near supernova maximum. They are exploring the nature of the collapse of the stellar core, specifically probing asymmetries in the explosion with spectropolarimetry. One key factor in determining the physical nature of core collapse supernovae is the geometry of portions of the ejecta of different composition. This is determined by careful spectropolarimetry. Dynamical models of core collapse that generate bipolar and more complex flows are being tested to determine the degree of fundamental asymmetry in the explosion necessary to imprint different polarization in different chemical layers of the ejecta. They participate in the use of the Robotic Optical Transient Source Experiment telescope array to study gamma-ray bursts, supernovae, and their connection.
Broader Impact: This work integrates research and education by advancing discovery and understanding, while at the same time educating graduate students and training postdoctoral researchers. The PI teaches a graduate course on supernova research that includes as active components many of the developments underway. In addition, the PI has long made it a practice to incorporate recent research developments into large classes for non-science majors, classes that are intrinsically diverse in terms of gender, ethnicity, disability, and geography. The PI also frequently publishes in the popular science literature and his work is featured in the new bilingual Texas Astronomy Education Center at McDonald Observatory. The PI has also worked to enhance the infrastructure of research by incorporating research on supernovae and gamma-ray bursts into an astrobiological context.
