摘要：Aims. Galaxy mass models based on simple and analytical functions for
density and potential pairs have been widely proposed in the literature. Disk models that
are constrained solely by kinematic data only provide information about the global disk
structure 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 give a more realistic
description of the density distribution in the disk component.
Methods. We produced fitted mass models from the disk model, which is
directly based on the observations divided into thin and thick stellar disks and H I and
H2 disks
subcomponents, 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 that 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.
Conclusions. The simple and analytical models for the mass distribution
in the Milky Way and their associated three-dimensional gravitational potential are able
to reproduce the observed kinematic constraints 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.
关键词：Galaxy: disk;Galaxy: fundamental parameters;Galaxy: kinematics and dynamics;Galaxy: structure;methods: numerical;methods: statistical
