Gaia Data Release 2 - Catalogue validation F. Arenou, X. Luri, C. Babusiaux, C. Fabricius, A. Helmi, T. Muraveva, A. C. Robin, F. Spoto, A. Vallenari, T. Antoja et al. (28 more) A&A, 616 (2018) A17 Published online: 20 August 2018 DOI: 10.1051/0004-6361/201833234