Internal Secular Evolution in Disk Galaxies: The Growth of Pseudobulges

Understand

Observational and theoretical evidence that internal, slow ("secular") evolution reshapes galaxy disks is reviewed in Kormendy & Kennicutt (2004, ARAA, 42, 603).

• This update has three aims.
• First, I emphasize that this evolution is very general -- it is as fundamental to the evolution of galaxy disks as (e.g.) core collapse is to globular clusters, as the production of hot Jupiters is to the evolution of protoplanetary disks, and as evolution to red giants containing proto-white-dwarfs is to stellar evolution.
• One consequence for disk galaxies is the buildup of dense central components that get mistaken for classical (i.e., merger-built) bulges but that were grown out of disk stars and gas.