The Peak Luminosity–Decline Rate Relationship for Type Ia Supernovae

Abstract

The peak luminosity–decline rate relationship for Type Ia supernovae is one of the most important underpinnings of modern cosmology. Reproducing it is also a fundamental test for any viable progenitor/explosion scenario. In this chapter, a short history of the discovery of the peak luminosity–decline rate relationship is presented, along with descriptions and comparisons of different methods used to characterize light curve shape. The importance of disentangling host galaxy dust reddening from intrinsic luminosity and color variations is also emphasized. It has been known for some time that certain spectral features correlate with decline rate and that these correspond to the amount of 56 N i produced in the explosion. Nevertheless, details regarding the progenitor and explosion mechanism(s) that create the tight relation observed between luminosity and decline rate are still lacking.