Different but still same: on the common origin of the peculiar Type Iax SNe

SNe Iax are possibly the most common subclass of the thermonuclear supernovae. However, only slightly more than a dozen objects have been studied in detail due to observational limitations. The Type Iax SNe are relatively faint explosions, as their peak absolute magnitude varies between -13.5 and -18.5 magnitude. The extreme diversity, which extends to other physical properties, raised the question, of whether multiple progenitor channels are contributing to the subclass. In recent years, new spectral time series observations have been added to both extremities of the Iax luminosity range. Together with a few intermediately luminous SNe, the slowly growing sample allows us to map the entire luminosity range of the group with various techniques, including spectral synthesis and abundance tomography. The direct comparisons of the derived physical and chemical properties indicate that the well-constrained parameters (including ejecta and radioactive Ni mass, expansion velocity, and spectral line evolution) show a continuous distribution in the subclass, which supports the theory that all SNe Iax share a similar origin. Considering the examples studied so far, the expansion velocity - luminosity correlation may also serve as a new way of distance estimation.