Spectropolarimetry of stripped-envelope supernovae: Observations and modelling

Spectropolarimetry is one of the most powerful methods to study the multi-dimensional geometry of supernovae (SNe). We present a brief summary of the spectropolarimetric observations of strippedenvelope core-collapse SNe. Observations indicate that stripped-envelope SNe generally have a nonaxisymmetric ion distribution in the ejecta. Three-dimensional clumpy geometry nicely explains the observed properties. A typical size of the clumps deduced from observations is relatively large: _⊙25% of the photosphere. Such a large-scale clumpy structure is similar to that observed in Cassiopeia A, and suggests that large-scale convection or standing accretion shock instability takes place at the onset of the explosion.