Virgo Cluster
| Virgo Cluster | |
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Virgo Cluster showing the diffuse light between member galaxies. Messier 87 is the largest galaxy (lower left).
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| Observation data (Epoch J2000) | |
| Constellation(s) | Virgo & Coma Berenices |
| Right ascension | 12h 27m |
| Declination | +12° 43′ |
| Brightest member | Messier 49 |
| Number of galaxies | ~1500 |
| Bautz-Morgan classification | III |
The Virgo Cluster is a cluster of galaxies whose center is 53.8 ± 0.3 Mly (16.5 ± 0.1 Mpc) away in the constellation Virgo. Comprising approximately 1300 (and possibly up to 2000) member galaxies, the cluster forms the heart of the larger Virgo Supercluster, of which the Local Group is an outlying member. However, the Local Group experiences the mass of the Virgo Supercluster as the Virgocentric flow. It is estimated that the Virgo Cluster's mass is 1.2×1015M☉ out to 8 degrees of the cluster's center or a radius of about 2.2 Mpc.
Many of the brighter galaxies in this cluster, including the giant elliptical galaxy Messier 87, were discovered in the late 1770s and early 1780s and subsequently included in Charles Messier's catalogue of non-cometary fuzzy objects. Described by Messier as nebulae without stars, their true nature was not recognized until the 1920s.
The cluster subtends a maximum arc of approximately 8 degrees centered in the constellation Virgo. Many of the member galaxies of the cluster are visible with a small telescope. Its brightest member is the elliptical galaxy Messier 49; however its most famous member is the also elliptical galaxy Messier 87, that unlike the former is located in the center of the cluster.
The cluster is a fairly heterogeneous mixture of spirals and ellipticals. As of 2004[update], it is believed that the spiral galaxies of the cluster are distributed in an oblong prolate filament, approximately four times as long as it is wide, stretching along the line of sight from the Milky Way. The elliptical galaxies are more centrally concentrated than the spiral galaxies.
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