Simultaneous polarization monitoring of supernovae SN 2008D/XT 080109 and SN 2007uy: isolating geometry from dust

Context. The possible existence of a continuum encompassing the diversity of explosive stellar deaths, ranging from ordinary supernovae (SNe; lacking any sign of a relativistic outflow) to relativistic hypernovae associated with energetic long duration gamma-ray bursts (GRBs), is under intense debate. In this context, the supernova SN 2008D associated with the X-ray transient (XT) 080109 could represent a paradigmatic case, since it might exemplify a potential borderline transition event. Optical polarimetric studies could contribute to shed light on the different interpretations given in the literature for this supernova (hereafter, SN 2008D/XT 080109).