Kinematics of the Milky Way from the Gaia EDR3 red giants and sub-giants

TL;DR

This study uses Gaia EDR3 data to analyze the kinematics of red giants and sub-giants in the Milky Way, deriving parameters that inform the Galaxy's rotational curve and velocity gradients without relying on the Sun's Galactocentric distance.

Contribution

It introduces a method to determine the Galactic rotational curve and its slope using spatial velocities, independent of the Sun's Galactocentric distance, based on Gaia EDR3 data.

Findings

Kinematic parameters align with previous literature.

Derived Galactic rotational curve and velocity gradients.

Alternative approach to infer Galactic dynamics.

Abstract

We present the results of the kinematic investigations carried out with the use of spatial velocities of red giants and sub-giants containing in the $Gaia$~EDR3 catalogue. The twelve kinematic parameters of the Ogorodnikov--Milne model have been derived for stellar systems with radii 0.5 and 1.0 kpc, located along the direction the Galactic center -- the Sun -- the Galactic anticenter within the range of Galactocentric distances $R$ 0--8--16~kpc. By combining some of the local parameters the information related to the Galaxy as a whole has been received in the distance range 4--12~kpc, in particular the Galactic rotational curve, its slope, velocity gradients. We show that when using this approach, there is an alternative possibility to infer the behaviour of the Galactic rotational curve and its slope without using the Galactocentric distance $R_\odot$. The kinematic parameters derived within the Solar vicinity of 1~kpc radius are in good agreement with those given in literature.