Mapping the diversity of Type Ia supernovae explosions

Type Ia supernovae (SNe Ia) are the explosive luminous deaths of accreting white dwarfs (WD) in binaries.

They play a vital role in chemical enrichment, galaxy feedback, and were instrumental in the discovery of dark energy, as our most mature cosmological probe.

However, next to these ""normal"" and cosmologically useful SNe Ia, a surprising diversity in WD explosions has been revealed, with a much wider-than-expected range in luminosities, light-curve timescales and spectral properties.

These ""peculiar"" events indicate that there are multiple ways a WD can explode and contaminate pure cosmological SNe Ia samples.

A promising path to relate these peculiar explosions with the numerous proposed theoretical models is by investigating their host galaxies and estimating the ages of their underlying stellar systems, as different progenitor scenarios involve different timescales that control the production rate of these events.

The aim of this action is to outline the variety and resolve the origins of these extreme SNe Ia.

I will use the current state-of-the-art ""discovery transient machine"", the Zwicky Transient Facility (ZTF), to compile the largest homogeneous sample of peculiar SNe Ia, characterise their population properties and host galaxy parameters, determine the ages of their progenitors and link them to theoretical progenitor channels.

By the end of this action, I will provide a detailed map of the SNe Ia diversity that will help decontaminate next-generation cosmological experiments, such as the Legacy Survey of Space and Time (LSST), and offer a significant advancement in understanding how a WD explodes.