Saturday, April 17, 2021

The beauty of Galaxies

Galaxies do not usually remain isolated in space, but tend to unite in groups held together by the force of gravity.
For example, the Milky Way belongs to the Local Group, of which it is one of the main components together with the Andromeda Galaxy and M33.
Groups of galaxies contain at most a few dozen components.
These small clusters of galaxies then tend to group together to form larger structures, named galaxy clusters, which usually contain between hundreds and thousands of members.
Some famous examples of galaxy clusters located in the local Universe are the Virgo Cluster and the Fornax Cluster.
The latter in particular is shown in this image obtained from ESO's VLT. It is located at a distance of 62 million light years and is therefore, after the Virgo Cluster, the second richest galaxy cluster located within 100 million light years away from us.
Thanks to its proximity it has been possible to study its evolution and structure in great detail. Observations on the dynamics of its components have shown that the cluster can be divided into two distinct subgroups.
The first is centered on NGC 1316, the lenticular galaxy visible on the left, which is also the brightest component of the cluster.
The second subgroup is instead centered on another lenticular galaxy, NGC 1399. The two sub-groups are getting closer to each other and in the future they will join together to form one large group.
A noteworthy component of the cluster that does not belong to any subgroup is NGC 1365, the beautiful barred spiral galaxy visible at the bottom right.
Credit: ESO, Aniello Grado, Luca Limatola.

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