Honors College Capstone Experience/Thesis Projects


Physics and Astronomy

Document Type



We seek to better understand the physical constraints under which White Dwarf stars ultimately become Type Ia supernovae (SNe Ia), an important test of the robustness of these tools in precisely measuring Dark Energy, as the definite progenitor system still remains elusive. The host galaxy environments of Type Ia supernovae provide our best opportunity for constraining the mechanism(s) of SN Ia production, i.e., the stars involved and the incubation times (tied to stellar ages), and the sensitivity of SNe Ia to changes in the local metallicity. We have measured the ages and metallicities of approximately 60 galaxies from a sample of Type Ia supernova hosts collected by the Nearby Galaxies Supernova Search project. In this manuscript, I present the completed analysis on 16 of these host galaxies, comparing their optical spectral data to synthesized galaxy models (from single stellar populations) to determine the dominant stellar ages and metallicities. Evidence shows a stronger dependence on the age of the host than the host’s metallicity, apparently conflicting with some predictions. These results are puzzling, but preliminary. A full analysis on all host data, and perhaps with more complex models, will provide a validity test of the mostly indirect trends established in other low-z surveys (e.g. Sloan Digital Sky Survey), and may ultimately steer future investigations for more precise SN Ia cosmology.

Advisor(s) or Committee Chair

Dr. Louis-Gregory Strolger


Astrophysics and Astronomy | Stars, Interstellar Medium and the Galaxy | The Sun and the Solar System