Star Bridge: Hubble photographs interacting galaxies

The specialists of the Hubble mission support group have published a new picture. It demonstrates the Arp 72 galaxy group.

The interacting group of galaxies Arp 72. Source: ESA/Hubble & NASA, L. Galbany, J. Dalcanton, Dark Energy Survey/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA

From the point of view of the “population”, Arp 72 is a fairly modest group. It consists of only two galaxies: NGC 5996 (a larger spiral galaxy) and NGC 5994 (its smaller companion, in the lower left corner of the image). They are located at a distance of about 160 million light-years from the Milky Way in the direction of the constellation Serpent.

The cores of NGC 5996 and NGC 5994 are separated from each other by a distance of 67 thousand light-years. Moreover, the distance between galaxies at their nearest points is even smaller and is about 40 thousand light-years. These are huge numbers from a human point of view, but quite small by galactic standards. For comparison, the Andromeda galaxy is 2.5 million light-years away. And the distance between the Milky Way and its largest satellite galaxy, the Large Magellanic Cloud, is about 162 thousand light-years.

Given this, as well as the fact that NGC 5996 is roughly comparable in size to the Milky Way, it is not surprising that the galaxies interact very actively with each other. This interaction has already caused the spiral arms of NGC 5996 to distort and extend in the direction of NGC 5994. 

Galaxies have also developed a “bridge” consisting of stars and gas. It departs from NGC 5996 in the upper right part of the image. Such tidal tails are a typical phenomenon in the convergence of galaxies, they can often be seen in images of such pairs.

According to https://esahubble.org

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