Type
Ia supernovae play a vital role in enriching the Universe with heavy elements,
shaping and heating the interstellar medium, and accelerating cosmic rays. The
energy released in these events, and the observed products of their
nucleosynthesis, indicate that they must be the explosions of carbon-oxygen
white dwarfs. But why should a white dwarf explode? The vast majority of models
invoke interaction with a companion star in a binary system, but the nature of
this interaction, and indeed the companion, remain a mystery.
In September 2010, the first Lorentz centre meeting on ``Observational
signatures of type Ia supernovae'' brought together theorists and observers
from all relevant disciplines to begin a concerted effort to address the
progenitor question. The great success of this meeting lead to a follow-up
workshop being held at the Lorentz centre in September, 2013, again a great
success. Considerable progress has since been made, with mounting observational
evidence favouring multiple channels playing a role in the production of type
Ia supernovae. The aim of this workshop is to discuss the significant progress
made since the last meeting, and to synthesize these recent successes in order
to take the next leap forward in understanding the nature of the progenitors of
type Ia supernovae.