Abstract
The stellar progenitors of type Ia supernovae (SNe Ia) remain a topic of active investigation, with the progenitors of superluminous 2003fg-like SNe Ia events particularly unclear. In this work, we explore the possibility that superluminous SNe Ia may originate from differentially-rotating C-O WD mergers resulting from binary white dwarfs. We utilize new self-consistent equilibria of differentially-rotating white dwarfs modeling the high-entropy envelope of the accreted secondary as initial conditions for our hydrodynamical models. We present nucleosynthetic yields and synthetic spectra obtained from the hydrodynamic models, and compare and contrast these synthetic results against sub-Chandrasekhar and near-Chandrasekhar white dwarf models. These results help shed light on the most extreme transients possible from the thermonuclear detonations of white dwarfs.