Gaia DR2 Gravitational Lens Systems I: New lensed quasar candidates around known quasars

Understand

Context.

• Strong gravitationally lensed quasars are among the most interesting and useful observable extragalactic phenomena.
• Because their study constitutes a unique tool in various fields of astronomy, they are highly sought, not without difficulty.
• Indeed, even in this era of all-sky surveys, their recognition remains a great challenge, with barely a few hundred currently known systems.