I discuss results from the COSMOS survey, showing that the fraction of disc
galaxies that is barred decreases considerably with look-back time from z ~ 0.2
to z ~ 0.8. This decrease is more important for small mass and low luminosity
spirals. Classical bar formation theory provides a promising framework for
understanding these results.
I also discuss the formation of discy bulges using N-body simulations
reproducing well the properties of observed discy bulges. Thus, these simulated
discy bulges have the shape of a disc, they have Sersic profiles with small
values of the shape index and their size is of the order of a kpc. They are
formed by radial inflow of material driven by the bar and are thus composed of
both gas and stars and have a considerable fraction of young stars. They can
harbour spiral structure, or an inner bar.Comment: 4 pages, 2 figures, contributed paper to the Rome meeting on
"Formation and Evolution of Galaxy Disks", eds, J. Funes, S.J. and E.M.
Corsin