Friday

Type Ia supernovae (SNe Ia) play a number of key roles in astrophysics. These include synthesising heavy elements such as iron, injecting kinetic energy in galaxy evolution and acting as cosmological distance indicators. Despite this, the way in which SNe Ia occur is still poorly understood and there is currently no definitive explosion scenario that explains SNe Ia. Thanks to modern transient surveys it has become clear that type Ia supernovae (SNe Ia) are a diverse population made up of a variety of sub populations. Type Iax supernovae (SNe Iax) are one such sub class which is estimated by Foley el al. (2013) to make up approximately 30% of the total SNe Ia rate. SNe Iax primarily occur in late-type host galaxies which implies they are a relatively young population and are spectroscopically similar to SNe Ia (although there are some differences) but generally have lower peak magnitudes. SNe Iax however have a much larger spread in their luminosity than normal SNe Ia: the faintest and brightest SNe Iax differ by more than 4 magnitudes at peak. A key theoretical challenge is understanding the origin of this diversity. In particular, to what degree can variations in the initial conditions account for the observed variety? To investigate this we present new three-dimensional, carbon-oxygen white dwarf deflagration models with varying initial conditions (ignition radius, central density, metallicity, non-rotating and rigidly-rotating models). We comment on the light curves and spectra produced from this series of models, including viewing-angle effects, and compare the synthetic observables to the SNe Iax population. From our models we find that significant diversity can be achieved but the full observed range of the SNe Iax class is not yet captured. Finally we discuss what may be driving the differences between the models and observed SNe Ia.