Structure, Activity, and Evolution of  Disk Galaxies

	              Shardha Jogee
	    (Space Telescope Science Institute)

Non-axisymmetric features (e.g., bars, spirals)  and  general triaxialities
(e.g., those of the bulge  and  halo)   drive the  dynamical  and  secular
evolution  of disk galaxies on all spatial scales by exerting gravitational
torques which redistribute mass and angular momentum.  In particular, these
features  control to  a large degree  the evolution of the inner kpc which
is the preferred site for   super  star clusters, intense  starbursts,  and
AGN activity in spiral galaxies. I will outline  how bar-driven gas inflow
can lead to a circumnuclear  molecular environment which differs  markedly
from the  outer disk  in terms of dynamics and  star formation properties.
I will outline  current controversies  and  possible  solutions concerning
dynamical mechanisms which  have been invoked for fueling  central AGN and
starbursts,  with a particular focus on nuclear  bars and spirals.  I will
discuss the properties  of  bars and  non-axisymmetric  features in local
spirals and  intermediate  redshift disks, along with  the  paradoxes and
possible implications for the  evolution of disk galaxies.