| This thesis presents a study of the progenitor ages of Type Ia supernovae (SNe Ia) by measurement of positional age indicators in spiral host galaxies, using both quantitative analyses and qualitative comparison with SNe II, which are known to be young objects. Using our own images of over 220 SN host galaxies in the V and I filters, we examine three age indicators: distance from spiral arms, disk scale height, and background color. The distribution of SNe Ia around spiral arms is significantly broader than that of SNe II and more similar to the light from the general stellar population, indicating that the SNe Ia arise from progenitors old enough (at least {dollar}5 times 10sp8{dollar} years) to have diffused away from their places of formation. An accurate measurement of the disk scale height of SNe is shown to be infeasible with the limited numbers of SNe detected in edge-on galaxies up to the present. The study of background colors of sites that have produced SNe shows much promise for age determination if additional factors such as accurate astrometry, aperture variation, and control apertures are taken into consideration. Our lower limit on the ages of SN Ia allows us to make distinctions among theoretical formation scenarios; we conclude that the most promising progenitor systems for SNe Ia may be coalescing white dwarf binaries. |
