Dr. Jeffrey M. Silverman is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at the University of Texas at Austin (UT). The fellow's research project centers on improving an important tool for measuring precise cosmological parameters: Type Ia supernovae. Type Ia supernovae (SNe Ia) are thermonuclear explosions of white dwarf stars, and because such features as their peak brightness and the rate at which they fade away are reliably predicable, they are used to measure distances to other galaxies. As a result, these supernovae help astrophysicists to measure cosmological parameters and to determine the expansion history of the Universe. Their use ultimately led to the discovery of the accelerating Universe, for which the Nobel Prize in Physics was awarded in 2011. The fellow will apply new distance measurement methods that utilize spectral observations in addition to photometric data in order to refine their use.
Despite their cosmological utility, astrophysicists still do not fully understand the process by which the exploding white dwarf reaches the Chandrasekhar limit, whether it actually reaches the limit (or significantly exceeds it in some cases), what progenitor scenarios and environments lead to SNe Ia, or the details of how the explosion itself occurs. To help resolve these and other issues, Dr. Silverman will explore the population of SN Ia host galaxies as well as undertake detailed studies of both "normal" and "peculiar" nearby, bright SNe Ia. Data for these in-depth investigations will be obtained at the very earliest times (i.e., hours after explosion) to 1--2 years past maximum brightness. These data will allow analyses of SNe Ia, their progenitor systems, and their explosion physics. Through this work Dr. Silverman aims to build up a more detailed picture of SNe Ia.
The broader impacts of this project include a significant educational component. The fellow will undertake a program of educational outreach in partnership with the McDonald Observatory to create new content for their multi-day summer Teacher Professional Development Workshops. He will base the new materials for the workshops around topics that are closely tied to his areas of expertise, such as supernovae, stellar evolution, and cosmology. Dr. Silverman will also develop new "Live From McDonald Observatory" video-conference programs for students throughout the state of Texas with associated hands-on activities. This material will be field-tested and refined with the help of local teachers and will be presented to teachers and science educators from around the state at the annual Conference for the Advancement of Science Teaching. This education program will directly impact hundreds of teachers and thousands of students in Texas, most of whom come from underrepresented populations and economically disadvantaged backgrounds.
