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Type | : | Supercluster | ─── | Galaxy Cluster Cloud | ─── | Galaxy Cluster |
Size | : | 77 Mpc | ─── | 23 Mpc | ─── | 8 Mpc |
Earth | : | Local Supercluster | ─── | Canes Venatici Cloud | ─── | Local Group |
Sometimes it is convenient to divide a supercluster into several groups of galaxy clusters, especially if the supercluster is a poor (irregular) one. Such groups are bigger than a galaxy cluster but smaller than a supercluster. We'll call them galaxy cluster clouds. It is not clear to me if there is a (different) standard name for them.
For example, the Local Supercluster has been divided into several clouds of galaxies (see the first table on the page about superclusters) [1], of which the Canes Venatici cloud harbors our own Galaxy. This cloud has the shape of a flat disk, 0.3 Mpc thick and with a radius of about 19 Mpc. This cloud of galaxies contains the Local Group and several galaxy clusters defined by [2], as listed in the following table. "G" stands for the de Vaucouleurs number of the group, "Name" is the proper name used by de Vaucouleurs, "Dist" is the revised distance from [2] (1973) in Mpc, "Brightest" lists the identification of the brightest member galaxy of the group, "B(0)" is the standard face-on B magnitude of that brightest member.
Table 1: Nearby Galaxy Clusters
G | Name | Dist | Brightest | B(0) |
---|---|---|---|---|
1 | Sculptor | 2.5 | NGC 253 | 8.1 |
2 | M 81 group | 3.0 | M 81 | 7.9 |
3 | CVn I | 4.5 | NGC 4736 | 8.9 |
4 | NGC 5128 group | 4.0 | NGC 5236 | 8.2 |
5 | M 101 group | 5.5 | M 101 | 8.6 |
10 | CVn II | 7.3 | NGC 4631 | 10.0 |
13 | Coma I | 8.1 | NGC 4725 | 10.2 |
17 | UMa I (Z) | 11.8 | NGC 4151 | 11.5 |
24 | UMa I (Y) | 14.7 | NGC 3776 | 11.1 |
28 | UMa I (X) | 10.7 | NGC 3310 | 11.2 |
32 | UMa I (S) | 15.2 | NGC 3938 | 11.0 |
34 | UMa I (N) | 12.8 | NGC 3992 | 10.8 |
41 | NGC 2768 group | 13.7 | NGC 2768 | 11.5 |
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Last updated: 2021-07-19