Near-Field cosmology with RR Lyrae variable stars: A first view of substructure in the southern sky

TL;DR

This study updates a spectroscopic survey of RR Lyrae stars in the southern sky to identify and analyze halo substructures, providing insights into the Milky Way's formation history.

Contribution

It offers new low-resolution spectroscopic data for RR Lyrae overdensities, improving the understanding of halo substructures in the southern sky.

Findings

Radial velocities and metallicities estimated for target stars.

Identification of potential halo substructure memberships.

Enhanced understanding of the Milky Way's halo composition.

Abstract

We present an update of a spectroscopic follow-up survey at low-resolution of a large number of RR Lyrae halo overdensity candidates found in the southern sky. The substructure candidates were identified in the RR Lyrae catalog of Torrealba et al. (2015) using Catalina Real-time Transient Survey (CRTS) data. Radial velocities and mean metallicities have been estimated for target stars in almost half of the original overdensities to assess their potential membership to coherent halo features.