Galaxy groups

The group of galaxies of the Hydra, nicknamed so because of the constellation which accommodates it, covers approximately 10 million light years and contains more than 100 brilliant galaxies.
The study of the radiation X emitted by the gas which it contains in quantity between its galaxies revealed an abnormally important proportion of dark matter.
Abell 1060 (A1060) is the other name given to this group hydra.
With the group of the Virgo and that of the Centaur (A3526), the group of the Hydra is one three bigger group of galaxies unless 200 million light years of the Milky Way.
It is current to refer to this region of the sky under the name of 'super clusters Virgo -Hydra - Centaurus'.

This group of galaxies is probably in the process of fusion. This amazing set of three galaxies is known group NGC 7771 lies about 200 million light-years away in the constellation Pegasus.
The largest barred spiral galaxy NGC 7771 (right), is about 75,000 light-years. It will absorb over time other galaxies to form one, even greater. Throughout their repeated passages close to one of the other, these galaxies will eventually merge into effect in a single large galaxy. Taking place over hundreds of millions of years, this process is part of the normal evolution of galaxies, that also will know our own galaxy, the Milky Way.

Among the billions of stars that merge into a single galaxy, probably few stars collide with each other due to the vast "empty" space. Red regions of galaxies are regions of star formation. The blue areas are hot young stars that have already formed. One can also observe regions of dust around galaxies that show the incredible amount of matter that exists around.

Image: The cluster of galaxies NGC 7771, includes NGC 7769 galaxy bottom left image, the large galaxy NGC 7771 on the right and the small galaxy NGC 7770 above NGC 7771. credit & copyright: Kent Biggs

Stephan's Quintet is a group of galaxies, that is a group of very close galaxies some of the others. It contains normally 5 main galaxies but only 4 are visible on this image. The galaxies incur because of their strong mass and it is likely that they will merge one day. The galaxies are strongly perturbed by the effect of their gravitational interaction.
We notice it on this image by the distended forms of the strands which extend very far from the center of the galaxy. The members of this group are NGC 7317, NGC 7318a, NGC 7318b, NGC 7319 and NGC 7320. If the first 4 galaxies form a relatively compact group, the fifth, NGC 7320 is away from the group but situated in the same region.

The Perseus cluster (Abell 426) is part of the Perseus-Pisces Supercluster (Pisces-Perseus) in the constellation of Perseus, 250 million light years. It contains about 190 galaxies and the Perseus-Pisces Supercluster contains about 1000 galaxies. This is one of the biggest visible sky objects. Almost all visible spots on the image are galaxies. The Perseus cluster is one of the closest galaxy clusters. The first star map belongs to our own Galaxy, the Milky Way, they are distinguished by their diffraction spikes. At the center of the cluster, the main galaxy of the cluster NGC 1275 can be seen, this is the largest galaxy visible on the left of the image. The galaxy NGC 1275 is a prodigious source of X-radiation and radio.

Seyfert Sextet is a group of galaxies located about 200 million light-years, in the head of the constellation Serpens. The constellation Serpens is the only constellation divided into two parts, the head and the tail, separated by the constellation Ophiuchus. The cluster galaxies Seyfert Sextet actually contains only 4 galaxies in gravitational interaction.
They are located in a small region of about 100 000 light-years, the size of our Galaxy. On the picture we see against the top center in the horizontal position, the galaxy NGC 6027 the brightest group galaxy, NGC 6027b upper right in oblique position, the spiral galaxy NGC 6027c horizontally and striped by a belt of dust clearly visible, it is located under NGC 6027b, NGC 6027e in the upper left has no bulb, it is not a galaxy of stars but simply a tail of stars hung by tidal effect to the nearby galaxy NGC 6027.