Researchers have found an amazing system of three galaxies. They form a long “tail” of gas and stars that stretches from the largest to the smallest of them. Astronomers believe that it has arisen as a result of the interaction of three bodies.
An international team of researchers has told about the discovery of an amazing group of galaxies connected by a long “tail” of gas and stars. The discovery was made as part of the DESI Legacy Imaging Surveys study.
It all started with the fact that during the search for previously unknown galaxies with low luminosity, astronomers discovered the PGC 1000273 star system. It is a lenticular galaxy that we see from the edge. It had an expressive tail and therefore received the nickname “Kite”.
Scientists have determined that the distance to it is 610 million light years and began to look for its companion. After all, it was clear that it could not get such a form without a tail. It turned out to be the galaxy PGC 070409 or Mrk 0926, located at a distance of 186 thousand light-years from it.
Both galaxies have active nuclei, which means that the supermassive black holes in their centers are constantly falling matter, causing intense radiation. This is a common pattern with such close interactions. Something else turned out to be strange. Mrk 0926 is located relative to the “Kite” not on the side of its “tail”, but on the opposite side.
The third galaxy and the “tail”
The system looks very strange. Mrk 0926 and PGC 1000273 are connected by a stream of gas and stars, which does not end at the second galaxy, but continues in a straight line from the other side behind it. At the same time, it is this part of it that is the largest.
The situation became a little clearer when a third galaxy was found in this long tail. It is much smaller than the previous two and was named Kite A. Its characteristic feature was the almost complete absence of signs of star formation. At the same time, at the very tail, it continues at full speed.
At the same time, this tail is the longest such structure that can be observed in visible light. Astronomers are also aware of longer intergalactic streams, but they are visible only in the radio range. All together, this makes the binary system truly unique.
How the system was formed
Astronomers found an explanation of how such a system was formed. We are talking about a rather rare case of interaction of three bodies simultaneously, in which each of them is an entire galaxy. Modern physics cannot solve this problem in a general way.
But the situation in the triple system looks quite understandable. In the triple interaction, the smallest galaxy by mass was ejected by the other two with great speed along a hyperbolic trajectory. This explains the extremely long and straight “tail”.
According to phys.org
Follow us on Twitter to get the most interesting space news in time