Determining the parameters of the spiral arms of the Galaxy from kinematic tracers based on Gaia DR3 data

TL;DR

This study uses Gaia DR3 data to accurately determine the parameters of the Milky Way's spiral arms, confirming their structure and positions with high statistical confidence.

Contribution

It introduces a method using stellar kinematic tracers to map spiral arms at large distances, providing new detailed parameters of the Galaxy's spiral structure.

Findings

Consistent spiral arm pitch angles with previous studies.

A schematic four-arm Galactic pattern is proposed.

High statistical confidence in the identified spiral structures.

Abstract

We present the results of determining the parameters of the spiral arms of the Galaxy using the stars Gaia DR3, whose absolute magnitude is $M_G$ < 4, and which allow tracing spiral arms at large distances from the Sun. As tracers of spiral arms, we use the centroids of stellar spherical regions with a radius of 0.5 kpc, in which the deformation velocities along the coordinate axis R are insignificant. These kinematic tracers cover the Galactic plane within the Galactocentric coordinate ranges 140{\deg} < ${\theta}$ < 220{\deg} and 4 kpc < R < 14 kpc. The numerical values of the pitch angles of the spirals and their Galactocentric distances to the point of intersection of the spiral with the direction of the Galactic center - the Sun are in good agreement with the results of other authors. By extrapolating beyond the data we have, we present a schematic four-arm global pattern, consisting of the Scutum-Centaurus, Sagitarius-Carina, Perseus, Norma-Outer arms, as well as the local arm Orion. The uncertainties of the determined spiral parameters confirm that the structures identified are not false, but are reliable from the statistical point of view.