Investigating the Unresolved Binary Population in Gaia DR3 Using Multi-Wavelength Photometry

Abstract

The Gaia DR3 and Non-Single-Star (NSS) catalogs are currently the definitive sources for binary systems (Gaia Collaboration 2023). While this affords an invaluable asset to the astronomical community, there are suspected limitations. To address these constraints, we introduce a filtering regime that can be applied to raw data. This study introduces the "Triple Constraint" framework for use on Gaia DR3 data through the application of multi-wavelength cogent evidence. Using Topcat, we cross-matched the WDS Supplement with the Gaia DR3, 2MASS, and Pan-STARRS catalogs. The derived "Base-sample" (N = 199,786) and "Quad-sample" (N = 120,418) provide the basis for the examination employed to establish systemic limits within the Gaia single-star model. To verify the results and eliminate any bias introduced by employing the WDSS as the basis for the Base and Quad-samples, we exploited an independent sample of Gaia-2MASS cross-matched audit stars, the "Audit-sample" (N = 22,371). Only stars selected at high northern declinations (delta > 60 degrees) were employed for this sample to avoid potential distortions resulting from crowding. All of these samples manifested a -0.75 magnitude offset, indicating the presence of two stars of equal magnitude, creating a "Detection Gap" across all populations. We conclude, reinforced by a peer-reviewed independent external spectroscopic study, that a 7% floor of global sensitivity exists, representing a limitation of the Gaia pipeline. This suggests that local stellar mass density models require a quantifiable correction to accurately reflect the local baryonic mass budget.