Dissecting galactic bulges in space and time I: the importance of early
  formation scenarios vs. secular evolution
  The details of bulge formation via collapse, mergers, secular processes or
their interplay remain unresolved. To start answering this question and
quantify the importance of distinct mechanisms, we mapped a sample of three
galactic bulges using data from the integral field spectrograph WiFeS on the
ANU 2.3m telescope in Siding Spring Observatory. Its high resolution gratings
(R=7000) allow us to present a detailed kinematic and stellar population
analysis of their inner structures with classical and novel techniques. The
comparison of those techniques calls for the necessity of inversion algorithms
in order to understand complex substructures and separate populations. We use
line-strength indices to derive SSP-equivalent ages and metallicities.
Additionally, we use full spectral fitting methods, here the code STECKMAP, to
extract their star formation histories. The high quality of our data allows us
to study the 2D distribution of different stellar populations (i.e. young,
intermediate, and old). We can identify their dominant populations based on
these age-discriminated 2D light and mass contribution. In all galactic bulges
studied, at least 50% of the stellar mass already existed 10 Gyrs ago, more
than currently predicted by simulations. A younger component (age between 1 to
8 Gyrs) is also prominent and its present day distribution seems to be affected
much more strongly by morphological structures, especially bars, than the older
one. This in-depth analysis of the three bulges supports the notion of
increasing complexity in their evolution, likely to be found in numerous bulge
structures if studied at this level of detail, which cannot be achieved by
mergers alone and require a non-negligible contribution of secular evolution.
