Dynamical evolution of massive perturbers in realistic multi-component
  galaxy models I: implementation and validation
  Galaxies are self-gravitating structures composed by several components
encompassing spherical, axial and triaxial symmetry. Although real systems
feature heterogeneous components whose properties are intimately connected,
semi-analytical approaches often exploit the linearity of the Poisson's
equation to represent the potential and mass distribution of a multi-component
galaxy as the sum of the individual components. In this work, we expand the
semi-analytical framework developed in Bonetti et al. (2020) by including both
a detailed implementation of the gravitational potential of exponential disc
(modelled with a ${\rm sech}^2$ and an exponential vertical profile) and an
accurate prescription for the dynamical friction experienced by massive
perturbers in composite galaxy models featuring rotating disc structures. Such
improvements allow us to evolve arbitrary orbits either within or outside the
galactic disc plane. We validate the results obtained by our numerical model
against public semi-analytical codes as well as full N-body simulations,
finding that our model is in excellent agreement to the codes it is compared
with. The ability to reproduce the relevant physical processes responsible for
the evolution of massive perturber orbits and its computational efficiency make
our framework perfectly suited for large parameter-space exploration studies.
