Scientists: the first galaxies the Universe was surrounded by «oceans» of dark matter

© Photo : NRAO/AUI/NSF; D. Eggplanty in the cluster J031132−5823.4, surrounded by an ocean of dark matterScientists: the first galaxies the Universe was surrounded by «oceans» of dark matter© Photo : NRAO/AUI/NSF; D. Berry

. Astronomers have discovered two giant galaxies that existed in the young Universe, and surrounded by a whole «ocean» of dark matter whose mass is in the trillions times the weight of the Sun, according to a paper published in the journal Nature.

«We used to consider that during adolescence the Universe it was inhabited by a large number of small galaxies, which are gradually ionized intergalactic medium and made it transparent to light and other forms of radiation. The latest pictures from the ALMA helped us figure out what is wrong and once again to push back the time when the Universe came the first really big galaxies, » said Daniel Marron (Daniel Marrone) from the University of Arizona in Tucson (USA).

The first galaxies, as scientists believe today, was the result of direct gravitational collapse of giant clouds of gas that formed in the void of the Universe due to small irregularities in the distribution of matter on it, generated by the gravitational «echo» of the ultrafast process of expansion of the Universe after the Big Bang.

Part of these clouds are turned into a single galaxies and other large objects, later became the ancestors of tens or hundreds of individual «star cities», United in clusters and galaxies superscope. At the end of last century astronomers, theorists suggested that the first galaxies in the Universe, inhabiting it in the first billion years of its existence, had to have a small size and weight.

In recent years, according to Marron, these theories began to be questioned – the Hubble, ALMA, and other telescopes of the world are constantly discovering more ancient and large galaxies that existed almost at the same time, when, as today, scientists believe, appeared the first stars, and the universe became completely transparent and available for observation.

Marroun and his colleagues accidentally discovered a pair of giant galaxies, which in principle do not fit into these theories, studying the stars and other light sources monitored by SPT infrared telescope mounted at the South pole. The main objective of this telescope – search for distortions in the microwave «echo» of the Big Bang, which arise due to its interaction with large clusters of galaxies.

Each time the SPT is quite large clusters, astronomers measure the distance to them, using the microwave telescope ALMA, is able to follow the movement of even the most cold molecules inside them. During one of these routine measurements, Marroun and his colleagues found that a small cluster of galaxies SPT0311−58, SPT was found in the constellation Hours, was located at a great distance from the Earth, and had giant sizes.

According to calculations of scientists, we see him in the condition in which it was 13 billion years ago, approximately 780 million years after the Big Bang. It consists of two large galaxies of comparable size with the Milky Way, each one heavier than the Sun 40 and 270 billion times. A significant part of this mass, as the researchers note, accounts for Stardust, in which early galaxies, astronomers doubted before.

The close proximity of these galaxies and the high speed of gas flows in them, in turn, suggests that they are surrounded by a kind of «ocean» of dark matter, not giving them the stars and other accumulations of matter to escape from SPT0311−58. Its mass, according to Marrone at least a trillion times bigger than the Sun, and this is the most conservative estimate.

As scholars have noted, such values exceed the maximum mass for «bagels» dark matter surrounding all galaxies. Marroun and his colleagues hope that the discovery of other objects of similar sizes will help scientists figure out whether SPT0311−58 exception to the rule, or a typical inhabitant of the young Universe.