Moving groups across Galactocentric radius with Gaia DR3

TL;DR

This paper introduces MGwave, a new wavelet-based method for detecting stellar moving groups in Gaia DR3 data, revealing their extent across the Milky Way and suggesting they are linked to galactic non-axisymmetric features.

Contribution

The paper presents MGwave, an improved wavelet transformation tool with robust significance testing, enabling detection of stellar moving groups across different Galactocentric radii using Gaia DR3.

Findings

Detected 47 stellar groups with coherent velocities in Gaia DR3.

Reproduced known moving groups and identified three new candidates.

Most groups extend across radii, indicating they are stellar streams related to galactic structure.

Abstract

The kinematic plane of stars near the Sun has proven an indispensable tool for untangling the complexities of the structure of our Milky Way (MW). With ever improving data, numerous kinematic "moving groups" of stars have been better characterized and new ones continue to be discovered. Here we present an improved method for detecting these groups using MGwave, a new open-source 2D wavelet transformation code that we have developed. Our code implements similar techniques to previous wavelet software; however, we include a more robust significance methodology and also allow for the investigation of underdensities which can eventually provide further information about the MW's non-axisymmetric features. Applying MGwave to the latest data release from Gaia (DR3), we detect 47 groups of stars with coherent velocities. We reproduce the majority of the previously detected moving groups in addition to identifying three additional significant candidates: one within Arcturus, and two in regions without much substructure at low $V_R$. Finally, we have followed these associations of stars beyond the solar neighborhood, from Galactocentric radius of 6.5 to 10 kpc. Most detected groups are extended throughout radius indicating that they are streams of stars possibly due to non-axisymmetric features of the MW.