Models for the 3-D axisymmetric gravitational potential of the Milky Way
  Galaxy - A detailed modelling of the Galactic disk
  Aims. Galaxy mass models based on simple and analytical functions for the
density and potential pairs have been widely proposed in the literature. Disk
models constrained by kinematic data alone give information on the global disk
structure only very near the Galactic plane. We attempt to circumvent this
issue by constructing disk mass models whose three-dimensional structures are
constrained by a recent Galactic star counts model in the near-infrared and
also by observations of the hydrogen distribution in the disk. Our main aim is
to provide models for the gravitational potential of the Galaxy that are fully
analytical but also with a more realistic description of the density
distribution in the disk component. Methods. From the disk model directly based
on the observations (here divided into the thin and thick stellar disks and the
HI and H$_2$ disks subcomponents), we produce fitted mass models by combining
three Miyamoto-Nagai disk profiles of any "model order" (1, 2, or 3) for each
disk subcomponent. The Miyamoto-Nagai disks are combined with models for the
bulge and "dark halo" components and the total set of parameters is adjusted by
observational kinematic constraints. A model which includes a ring density
structure in the disk, beyond the solar Galactic radius, is also investigated.
Results. The Galactic mass models return very good matches to the imposed
observational constraints. In particular, the model with the ring density
structure provides a greater contribution of the disk to the rotational support
inside the solar circle. The gravitational potential models and their
associated force-fields are described in analytically closed forms, and in
addition, they are also compatible with our best knowledge of the stellar and
gas distributions in the disk component. The gravitational potential models are
suited for investigations of orbits in the Galactic disk.
