structural:scholar_edition, stylistic:style_transfer, information:highlighting, quality:correction
Environment

M87 is near (or at) the center of the Virgo Cluster, a closely compacted structure of about 2,000 galaxies. This forms the core of the larger Virgo Supercluster, of which the Local Group (including the Milky Way) is an outlying member. It is organized into at least three distinct subsystems associated with the three large galaxies—M87, M49 and M86 —with the core subgroup including M87 (Virgo A) and M49 (Virgo B). There is a preponderance of elliptical and S0 galaxies around M87. A chain of elliptical galaxies roughly aligns with the jet. In terms of mass, M87 is likely to be the largest, and coupled with centrality appears to be moving very little relative to the cluster as a whole. It is defined in one study as the cluster center. The cluster has a sparse gaseous medium that emits X-rays, lower in temperature toward the middle. The combined mass of the cluster is estimated to be 0.15 to 1.5 × 10 M.

Measurements of the motion of those intracluster starburst ("planetary") nebulae between M87 and M86 suggest that the two galaxies are moving toward each other and that this may be their first encounter. M87 may have interacted with M84, as evidenced by the truncation of M87's outer halo by tidal interactions. The truncated halo may also have been caused by contraction due to an unseen mass falling into M87 from the rest of the cluster, which may be the hypothesized dark matter. A third possibility is that the halo's formation was truncated by early feedback from the active galactic nucleus.