Virgo Cluster

The Virgo Cluster consists of galaxies at a distance of around 59 Mly away in the constellation Virgo. Containing between 1300 to 2000 galaxies the Virgo Cluster is the heart of the Local Supercluster. Its mass is estimated at 1.2 × 1015 M☉ out to 8 degrees of the cluster’s center or a radius of about 2.2 Mpc.

Most of the brighter galaxies in the cluster were discovered by Charles Messier in the late 1770’s and early 1780’s, including the giant elliptical Messier 87. Messier subsequently catalogued these galaxies as non-cometary fuzzy objects, which were described as nebulae without stars. Their true nature was recognized in the 1920’s.
Centered in the Constellation Virgo the cluster subtends a maximum arc of approximately 8 degrees and many of the galaxies are visible with a small telescope. The cluster is a mix of spiral and elliptical galaxies. The spirals are distributed in an oblong prolate filament stretching along the line of sight from the Milky Way. The Elliptical galaxies are concentrated in the center more so than the spiral galaxies. The cluster is composed of three separate subclumps with the most dominate centered on M87, while the other two galaxies are M87 and M86. The dominate subclump has a mass of approximately 1014 solar masses, which is approximately an order of magnitude larger than the other two subclumps.

The large mass of the cluster is indicated by the high peculiar velocities of many of its galaxies, sometimes as high as 1,600 km/s with respect to the cluster’s center.

The large mass of the Virgo Cluster has the effect of slowing down the larger Local Supercluster that it is within. The gravitational effects slow down the recession of the Local Group by approximately ten percent.

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