NGC 4374

Messier 84 (NGC 4374) is a large elliptical galaxy in the constellation Virgo and one of the brightest members of the Virgo Cluster of galaxies, approximately 60 million light-years from Earth. Charles Messier discovered it on March 18, 1781. NGC 4374 is classified as type E1 — nearly round — though some astronomers believe it may actually be a face-on lenticular (S0) galaxy, a type intermediate between spirals and ellipticals that retains a disk but lacks prominent spiral arms. M84 lies near the gravitational center of the Virgo Cluster and can be seen in the same wide-field view as M86 and a chain of other Virgo galaxies known as Markarian's Chain.

NGC 4374 harbors an active galactic nucleus: a supermassive black hole estimated at around 1.5 billion solar masses that produces two oppositely directed jets visible at radio wavelengths — a classic signature of a low-luminosity AGN driving outflows into the surrounding galaxy. The main visible body of the galaxy is otherwise smooth and featureless, as expected for a massive elliptical without ongoing star formation. M84 is embedded in a halo of hot X-ray emitting gas that extends far beyond the visible galaxy, a common feature of massive ellipticals in dense cluster environments where supernovae and AGN heating prevent the hot gas from cooling.

In a small telescope M84 appears as a bright, round, featureless glow alongside M86 just half a degree away; the two are best observed together as a pair in a moderate-power field. This image was made at the Kitt Peak National Observatory 0.9-meter telescope in December 1996.