Mapping the Milky Way Disk with Gaia DR3: 3D extended kinematic maps and rotation curve to $\approx 30$ kpc

TL;DR

This paper uses Gaia DR3 data and a statistical deconvolution method to create detailed 3D kinematic maps of the Milky Way up to 30 kpc, revealing asymmetrical motions and a declining rotation curve.

Contribution

It applies an improved Lucy's inversion method to Gaia DR3 data, producing more accurate and extensive kinematic maps and rotation curve measurements of the Milky Way.

Findings

Milky Way shows asymmetrical motions with significant velocity gradients.

The rotation curve declines significantly up to 27.5 kpc.

Vertical dependence of rotation velocity is notable within 15 kpc.

Abstract

We apply a statistical deconvolution of the parallax errors based on Lucy's inversion method (LIM) to the Gaia-DR3 sources to measure their three dimensional velocity components in the range of Galactocentric distances $R$ between 8 kpc and 30 kpc with their corresponding errors and root mean square values. We find results that are consistent with those obtained by applying LIM to the Gaia-DR2 sources, and we conclude that the method gives convergent and more accurate results by improving the statistics of the data-set and lowering observational errors. The kinematic maps reconstructed with LIM up to $R \approx 30$ kpc show that the Milky Way is characterized by asymmetrical motions with significant gradients in all velocity components. Furthermore, we determine the Galaxy rotation curve $V_C(R)$ up to $\approx 27.5$ kpc with the cylindrical Jeans equation assuming an axisymmetric gravitational potential. We find that $V_C(R)$ is significantly declining up to the largest radius investigated. Finally, we also measure $V_C(R)$ at different vertical heights, showing that, for $R <15$ kpc, there is a marked dependence on $Z$, whereas at larger $R$ the dependence on $Z$ is negligible.