The astronomers worked out how much «weight» of the galaxy after a merger

© Photo : NASA/CXC/M. WeissТак the artist has pictured two merging elliptical galaxiesThe astronomers worked out how much «weight» of the galaxy after a merger© Photo : NASA/CXC/M. Weiss

Supercomputer model of the Universe has helped scientists figure out what the colliding galaxies will almost always lose up to a third of their dark and visible matter after the merger with each other, regardless of the size of the clusters in which they live, is spoken in article placed in electronic library arXiv.org

«If we can figure out how much weight you lose galaxies during this process, we will be able to understand what the physical laws and processes orchestrate the growth and life of galaxies. This is extremely important for a complete picture of how galaxy evolyutsioniruet in particularly dense parts of space,» says Gandhali Joshi (Gandhali Joshi) from McMaster University in Montreal (Canada).

According to modern concepts, collisions and mergers of galaxies are quite commonplace. On the other hand, it is not clear how often these things happened in «childhood» and «adolescence» of the Universe. According to NASA, from 5% to 25% visible galaxies collide or have already merged with their nearest neighbours, and in the past frequency of such events could be much higher than today.

As Joshi says, such as collision, as previously thought by scientists, occur in different ways in large clusters of galaxies and between single galaxies or small «families» of 20-30 of these objects.

In the first case, as shown by the observation of clusters of hundreds of thousands of galaxies, their merger lead to the fact that the final galaxy loses a considerable part of his dark matter. It «eats» the Central part of clusters where the most difficult of his life. When the merger of individual galaxies and galaxies in small groups, as previously thought by scientists, nothing of the kind.

Supercomputer model of the Universe created by Joshi and her colleagues, shows that it’s actually not so – the galaxies in these small «families» virtually always lose about 35-40% of its weight when merged with each other and only when the associations with larger clusters of galaxies.

Interestingly, the galaxy’s lone avoid a similar fate – they lose about 12% of its weight when you join a large «family». On the other hand, they begin to «lose weight» under the influence of gravity of other galaxies of the group are much faster than a «family» of the galaxy, which eventually balances their losses.

The main driving factor in the «weight loss» of galaxies, according to the calculations of astrophysicists, are clumps of dark matter that makes galaxies lose mass before they joined their new «family». As I hope the authors, their calculations will help us to understand what is dark matter and how it «conducts» life and evolution of the largest clusters of stars in the Universe.

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