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Lensed quasars occur when the light from a distant quasar is bent by the gravitational field of an intervening galaxy, creating multiple images or a magnified view of the distant object. Studying these lensed quasars can reveal critical clues about dark matter distribution, the expansion rate of the universe, and the formation of large-scale cosmic structures.
The Gaia data's richness offers astronomers new opportunities to explore the earliest epochs of the cosmos, shedding light on how galaxies and supermassive black holes evolved during the universe’s formative years.