12.1 Introduction

Author(s): David Teyssier, Coryn Bailer-Jones

Gaia DR3 provides for the first time two new tables that integrate the outputs of DPAC processing modules dedicated to extragalactic objects. While the processing details leading to the generation of these products are explained in previous chapters, we describe in this chapter the content of these tables and how they have been constructed (Section 12.2), how their source attributes are distributed (Section 12.3), and provide some recommendations on their use (Section 12.4). Further validation aspects are also covered in Chapter 14 and complementary information about the scientific exploitation of these tables is given in Gaia Collaboration et al. (2023b).

We emphasise that these tables have been populated following a completeness-driven selection, especially in one of the classifier modules they integrate (DSC – see Section 11.3.2). As such they have a low purity level and contain a large number of non-genuine extragalactic sources. This will allow users to devise alternate selection of the most reliable quasars and galaxies from these tables according to their own criteria. We also provide various recipes in order to draw purer samples in Section 12.4.