  We present a detailed comparison between the photometric properties of the
bulges of two simulated galaxies and those of a uniform sample of observed
galaxies. This analysis shows that the simulated galaxies have bulges with
realistic surface brightnesses for their sizes and magnitude. These two field
disc galaxies have rotational velocities ~ 100 km/s and were integrated to a
redshift of zero in a fully cosmological Lambda cold dark matter context as
part of high-resolution smoothed particle hydrodynamic simulations. We
performed bulge-disc decompositions of the galaxies using artificial
observations, in order to conduct a fair comparison to observations. We also
dynamically decomposed the galaxies and compared the star formation histories
of the bulges to those of the entire galaxies. These star formation histories
showed that the bulges were primarily formed before z = 1 and during periods of
rapid star formation. Both galaxies have large amounts of early star formation,
which is likely related to the relatively high bulge-to-disc ratios also
measured for them. Unlike almost all previous cosmological simulations, the
realistically concentrated bulges of these galaxies do not lead to unphysically
high rotational velocities, causing them to naturally lie along the observed
Tully-Fisher relation.
