M60 - NGC 4649

Messier 60 (NGC 4649) is a giant elliptical galaxy located approximately 55 million light-years from Earth in the constellation Virgo. It is the third brightest giant elliptical galaxy in the Virgo Cluster, after M49 and M87, and was discovered by Johann Gottfried Koehler in April 1779, with Charles Messier cataloging it independently that same month. M60 is classified as an E2 elliptical galaxy and has a visual magnitude of about 8.8, making it one of the brighter galaxies in the Virgo Cluster. The galaxy has a diameter of approximately 120,000 light-years and is estimated to contain about 400 billion stars. At its center lies one of the most massive black holes known, with a mass estimated at 4.5 billion solar masses, roughly a thousand times the mass of the Milky Way's central black hole. M60 is surrounded by an extensive system of approximately 5,100 globular clusters. One of M60's most notable visual features is its close apparent companion, the spiral galaxy NGC 4647, which appears to overlap with M60's outer halo. For decades astronomers debated whether the two galaxies were physically interacting or merely a chance alignment, but Hubble Space Telescope images revealed tidal distortions confirming a genuine interaction. In 2012, an ultracompact dwarf galaxy named M60-UCD1 was discovered orbiting M60, which despite being only 160 light-years across contains a 21-million solar mass black hole. Through amateur telescopes, M60 appears as a bright, round, featureless glow with a strong central concentration. It forms an attractive pair with NGC 4647 in moderate to large telescopes.

M60 spans about 120,000 light-years in diameter, contains roughly 400 billion stars, and harbors a 4.5 billion solar mass central black hole.