Search for Stellar Streams Based on Data from the RAVE5 and Gaia TGAS Catalogues

TL;DR

This study identifies stellar streams in Gaia and RAVE data, notably linking a group of stars to the debris of globular cluster 0 Cen, revealing insights into their kinematic and chemical properties.

Contribution

The paper introduces a method to detect stellar streams using combined Gaia TGAS and RAVE5 data, identifying a new stream associated with Cen debris.

Findings

Identified three stellar clumps with large velocities in the velocity plane.

Linked the BB17-3 clump to debris from globular cluster Cen.

Discovered 28 stars with low velocity dispersion and similar ages in the BB17-3 clump.

Abstract

We have analyzed the space velocities of stars with the proper motions and trigonometric parallaxes from the Gaia TGAS catalogue in combination with the line-of-sight velocities from the RAVE5 catalogue. In the (V,\sqrt{U^2+2V^2}) velocity plane we have identified three clumps, BB17-1, BB17-2, and BB17-3, in the region of large velocities (V<-150 km/s). The stars of the BB17-1 and BB17-2 clumps are associated with the kinematic groups VelHel-6 and VelHel-7 detected previously by Helmi et al. We give the greatest attention to the BB17-3 clump. The latter is shown to be most closely linked with the debris of the globular cluster \omega Cen. In the BB17-3 clump we have identified 28 stars with a low velocity dispersion with respect to the center of their distribution. All these stars have very close individual age estimates: \log t\approx 10. The distribution of metallicity indices in this sample is typical for the stars of the globular cluster \omega Cen. In our opinion, the BB17-3 clump can be described as a homogeneous stream in the debris of the cluster \omega Cen.