Type Ia Supernovae BT - Handbook of Supernovae

Abstract

Type Ia supernovae play an important role in many areas of astrophysics, as extragalactic distance indicators and the most mature probes of cosmic acceleration, as the main producers of iron in the Universe, as end points of stellar evolution, and as contributors to the chemical evolution of galaxies. While Type Ia supernovae have long been hypothesized to result from the thermonuclear explosions of carbon-oxygen white dwarfs, the stellar systems that produce these events and their explosion mechanisms are still very much under debate. The aim of this chapter is to describe the observational characteristics of Type Ia supernovae, ranging from their light curve and spectral properties to constraints from the galaxies within which they explode. Although they are a predominantly optical phenomenon, their observational signatures from gamma-ray to radio wavelength are discussed. An overview of the potential channels through which they could explode is also provided, along with the best current observational tests of the different scenarios. The use of Type Ia supernovae in modern cosmology, in the context of light curve-luminosity correlations, is also discussed.