Surfing on the bar: the formation of anti-truncated stellar disk profiles

The stellar radial profiles of disk galaxies are often observed to be truncated, or anti-truncated in the galaxies' outskirts. As of now, the literature about galaxy formation lacks a model for the formation of observed anti-truncated stellar disks which is based on secular processes. We present an attempt to fill this gap. We were able to model anti-truncated disks in numerical SPH simulations of the formation of isolated galaxies. We will show that the stars in the outskirts of the simulated galactic disk are on very eccentric orbits but were formed on circular orbits at much smaller radii. We argue that a strong central bar is the main driver of the formation of such a disk configuration. The model predicts that such outer stellar disks should show very slow rotation, but high radial dispersion. If confirmed, their existence would constitute galaxy disks of qualitatively very new kinematic properties.