# Models for the 3-D axisymmetric gravitational potential of the Milky Way Galaxy - A detailed modelling of the Galactic disk

**Authors:** D. A. Barros, J. R. D. Lépine, W. S. Dias  
**arXiv:** [1607.02541](https://arxiv.org/abs/1607.02541)  
**Date:** 2016-07-08  
**Summary page:** https://www.summarizepaper.com/en/paper/1607.02541v1/

## Key points

- Study focuses on constructing models for the three-dimensional axisymmetric gravitational potential of the Milky Way galaxy, specifically targeting the Galactic disk
- Previous mass models lacked a realistic description of density distribution in the disk component
- Authors propose constructing disk mass models constrained by recent observations of star counts and hydrogen distribution in the disk
- Model divided into thin and thick stellar disks as well as HI and H2 disks subcomponents
- Combination of three Miyamoto-Nagai disk profiles used for each subcomponent to create fitted mass models
- Models adjusted based on observational kinematic constraints
- Investigated model includes a ring density structure in the disk beyond the solar Galactic radius
- Results show excellent matches to imposed observational constraints, with significant contribution from ring density structure inside the solar circle
- Gravitational potential models derived from this study described analytically and in closed forms
- Provides more realistic descriptions of density distribution in galactic disks while maintaining fully analytical gravitational potential models

## Summary

This study focuses on constructing models for the three-dimensional axisymmetric gravitational potential of the Milky Way galaxy, specifically targeting the Galactic disk. Previous mass models have relied on simple and analytical functions for density and potential pairs; however, they often lack a realistic description of the density distribution in the disk component. To overcome this limitation, the authors propose constructing disk mass models that are constrained by recent observations of star counts in the near-infrared and hydrogen distribution in the disk. The authors divide their model into thin and thick stellar disks as well as HI and H2 disks subcomponents. They use a combination of three Miyamoto-Nagai disk profiles (of different "model orders") for each subcomponent to create fitted mass models. These Miyamoto-Nagai disks are then combined with models for the bulge and "dark halo" components. The parameters of these models are adjusted based on observational kinematic constraints. In addition to these components, a model is investigated which includes a ring density structure in the disk beyond the solar Galactic radius. The results show that these Galactic mass models provide excellent matches to imposed observational constraints; notably, the model with a ring density structure contributes significantly to rotational support inside the solar circle. The gravitational potential models derived from this study are described analytically and in closed forms; they not only accurately represent our best knowledge of stellar and gas distributions in the Galactic disk but also enable investigations of orbits within it. Overall, this research provides more realistic descriptions of density distribution in galactic disks while maintaining fully analytical gravitational potential models.