  Polar Ring Galaxies, such as NGC4650A, are a class of galaxy which have two
kinematically distinct components that are inclined by almost 90 degrees to
each other. These striking galaxies challenge our understanding of how galaxies
form; the origin of their distinct components has remained uncertain, and the
subject of much debate. We use high-resolution cosmological simulations of
galaxy formation to show that Polar Ring Galaxies are simply an extreme example
of the angular moment misalignment that occurs during the hierarchical
structure formation characteristic of Cold Dark Matter cosmology. In our model,
Polar Ring Galaxies form through the continuous accretion of gas whose angular
momentum is misaligned with the central galaxy.
