Type Ia Supernovae from violent white dwarf mergers

Abstract:
The progenitor system(s) and explosion mechanism of Type Ia Supernovae (SNe Ia) are still unknown. Recently, increasing 
evidence has been accumulated, that at least some SNe Ia are mergers of two white dwarfs. As we have shown in previous 
studies, violent mergers reproduce observed lightcurves and spectra of normal SNe Ia well. In the violent merger scenario, a 
detonation forms directly  during the merger and the whole merging object is disrupted in the SN explosion.
Similar to most SNe Ia scenarios, the critical point for the violent merger scenario is whether the detonation forms during the 
merger or not.
Although high-resolution smoothed particle hydrodynamics (SPH) simulations of white dwarf mergers have shown indications 
that a detonation may form, it is not enough to decide this question yet.
Here, I will present latest results of high-resolution merger simulations obtained with SPH and a finite-volume moving-mesh 
code. I will show how the properties of the white dwarf merger depend on the hydrodynamics scheme employed and focus 
particularly on the part that may lead to the formation of a detonation. Moreover, I will show how a merger of two carbon-oxygen 
white dwarf robustly causes the formation of a detonation.
Finally, I will discuss the implications of this explosion mechanism of violent mergers for the general population of SNe Ia.