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Elegant spiral galaxy hides a hungry monster
NGC 4639 is a beautiful example of a type of galaxy known as a barred spiral. It lies over 70 million light-years away in the constellation of Virgo and is one of about 1500 galaxies that make up the Virgo Cluster. But NGC 4639 also conceals a dark secret in its core — a massive black hole that is consuming the surrounding gas and known as an active galactic nucleus (AGN).