Finding evolved stars in the inner Galactic disk with Gaia

TL;DR

This study aims to identify evolved stars in the inner Galactic disk by cross-matching the BAaDE survey with Gaia data, enabling detailed stellar population analysis despite optical extinction.

Contribution

It presents an initial cross-matching approach between BAaDE and Gaia, refining candidate selection for evolved stars in the Galactic bulge.

Findings

Over 5,000 Gaia candidates identified from BAaDE targets

Approximately half expected to show SiO emission for velocity data

Refined cross-matching criteria reduce false positives

Abstract

The Bulge Asymmetries and Dynamical Evolution (BAaDE) survey will provide positions and line-of-sight velocities of ~20,000 evolved, maser bearing stars in the Galactic plane. Although this Galactic region is affected by optical extinction, BAaDE targets may have Gaia cross-matches, eventually providing additional stellar information. In an initial attempt to cross-match BAaDE targets with Gaia, we have found more than 5,000 candidates. Of these, we may expect half to show SiO emission, which will allow us to obtain velocity information. The cross-match is being refined to avoid false positives using different criteria based on distance analysis, flux variability, and color assessment in the mid- and near-IR. Once the cross-matches can be confirmed, we will have a unique sample to characterize the stellar population of evolved stars in the Galactic bulge, which can be considered fossils of the Milky Way formation.