Secular building of galaxy bulges (Dimitri Gadotti, ESO)

Disk galaxies undergo several evolutionary processes that shape their
current observed properties. Dynamical instabilities in the disk
originate stellar bars, which redistribute angular momentum along the
galaxy, bringing gas and stars to the center, and thus helping to
secularly build the central, bulge component. In this talk, I will
focus on results from 2D, multi-band bulge/bar/disk decompositions of
nearly 1000 galaxies in the local universe. The results indicate, with
high statistical significance, that indeed, secularly built, disk-like
pseudobulges are formed differently than classical bulges, which are
thought to form through fast, violent processes, like mergers. Bars
and disk-like bulges share a similar slope for their mass-size
relation, which is different from that of classical bulges at a 5
sigma confidence level. I will also show how this work provides a
complete picture of the structural properties of bulges, disks and
bars at low redshifts, and how they can be used to test galaxy
evolution models.