Spin-up of massive classical bulges during secular evolution
  Classical bulges in spiral galaxies are known to rotate but the origin of
this observed rotational motion is not well understood. It has been shown
recently that a low-mass classical bulge (ClB) in a barred galaxy can acquire
rotation from absorbing a significant fraction of the angular momentum emitted
by the bar. Our aim here is to investigate whether bars can spin up also more
massive ClBs during the secular evolution of the bar, and to study the
kinematics and dynamics of these ClBs. We use a set of self-consistent N-body
simulations to study the interaction of ClBs with a bar that forms
self-consistently in the disk. We use orbital spectral analysis to investigate
the angular momentum gain by the classical bulge stars. We show that the ClBs
gain, on average, about 2 - 6% of the disk's initial angular momentum within
the bar region. Most of this angular momentum gain occurs via low-order
resonances, particularly 5:2 resonant orbits. A density wake forms in the ClB
which corotates and aligns with the bar at the end of the evolution. The
spin-up process creates a characteristic linear rotation profile and mild
tangential anisotropy in the ClB. The induced rotation is small in the centre
but significant beyond $\sim2$ bulge half mass radii, where it leads to
mass-weighted $V/\sigma \sim 0.2$, and reaches a local $V_{max}/\sigma_{in}
\sim 0.5$ at around the scale of the bar. The resulting $V/\sigma$ is tightly
correlated with the ratio of the bulge size to the bar size. In all models, a
box/peanut bulge forms suggesting that composite bulges may be common.
Bar-bulge resonant interaction in barred galaxies can provide some spin up of
massive ClBs, but the process appears to be less efficient than for low-mass
ClBs. Further angular momentum transfer due to nuclear bars or gas inflow would
be required to explain the observed rotation if it is not primordial.
