Velocity-space substructure from nearby RAVE and SDSS stars

TL;DR

This study identifies and analyzes velocity-space substructures in nearby disc stars from RAVE and SDSS, confirming previous findings and linking them to Lindblad resonances, thus enhancing understanding of stellar dynamics.

Contribution

It demonstrates the presence of velocity-space substructure in independent datasets and links these features to Lindblad resonances using action-angle variables.

Findings

Velocity-space substructure confirmed in RAVE and SDSS data.

Hyades stream stars show characteristics of Lindblad resonance scattering.

Local samples cannot distinguish resonance type or pattern multiplicity.

Abstract

We extract a sample of disc stars within 200 pc of the Sun from the RAVE and SDSS surveys. Distances are estimated photometrically and proper motions are from ground-based data. We show that the velocity-space substructure first revealed in the Geneva-Copenhagen sample is also present in this completely independent sample. We also evaluate action-angle variables for these stars and show that the Hyades stream stars in these data are again characteristic of having been scattered at a Lindblad resonance. Unfortunately, analysis of such local samples can determine neither whether it is an inner or an outer Lindblad resonance, nor the multiplicity of the pattern.