active galactic nucleus – Astronomy Now

Seek out 3C 273, the brightest optical quasar, in the spring sky

7 March 2019 Ade Ashford

Plumb the hidden depths of spring’s deep-sky by seeking out 3C 273, the optically-brightest quasi-stellar object (QSO) in the constellation of Virgo. Quasars are the intensely luminous centres of very distant and active galaxies, powered by a supermassive black hole. And don’t worry that you need a huge ‘scope to see it – a 15-cm (6-inch) instrument and a clear, moonless night are all you need.

Elegant spiral galaxy hides a hungry monster

16 October 2015 Astronomy Now

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).