Discover a number of previously unknown small galaxiesScientists suggest that such galaxies, such as Segue-1, Bootes I, II and Tucana Ursa Major I, one of the first galaxies, have been formed and that their age is over 13 billion years, writes Chronicle.info with reference to 24news.com .ua
The first atoms appeared when the universe was 380 thousand years old. These were the atoms of hydrogen – the simplest element on the periodic table. They gathered in clouds and were gradually cooled down, turning into small bundles or "halo" dark matter created from the big bang.
This phase of cooling, known as the "cosmic dark ages & # 39; that lasted about 100 million years. Eventually the gas cooled down in the halo's, became unstable and began to form stars: these objects are the first of the galaxy. After their formation, the universe was filled with light, ending "dark times".
Dr. Shounak Bose from the Harvard-Smithsonian center for astrophysics, Dr. ir. Alice Dyson and Professor Carlos Frenk of the University of Durham have identified two populations of satellite galaxies. The first was a very weak population of galaxies occurring in the dark ages & # 39; formed. The second is a livelier population consisting of galaxies that appeared hundreds of millions of years later, when the hydrogen ionized intense ultraviolet radiation emitted by the first stars, could cool to a massive halo of dark matter.
Scientists discovered that the model of the formation of galaxies, previously developed by them, perfectly matches the data obtained. This allowed them to calculate the periods of satellite system formation. A study published in the journal The Astrophysical journal.
"To detect some of the first galaxies that orbit the Milky Way in our universe – astronomy corresponds to the discovery of the remains of the first people to inhabit the Land – it's incredibly exciting, says Professor Carlos Frenk. discovery supports the current model of evolution of the universe is Λ CDM ("Lambda-Sidim"), in which the elementary particles that form dark matter are driven by the cosmic evolution ".
Intense ultraviolet radiation emitted by the first galaxies destroyed the remaining hydrogen atoms, caused them to dislodge (turning off electrons), preventing this gas from cooling down and forming new stars. The process of galactic formation stopped and new galaxies appeared for about a million years.
As a result, the halo of the dark matter has become so massive that even the ionized gas could cool. Galactic formation is resumed, culminicola the formation of extremely bright galaxies such as the Milky Way.
"One of the nice aspects of this work is that it emphasizes the correspondence between theoretical model predictions and factual data," says Dr. Sounak Bowes, where ten years ago the very weak galaxies near the galaxy would go unnoticed. of modern equipment a number of previously unknown small galaxies were discovered with which we could test the theoretical model in the new regime. "
"This is a good example of how observation of the smallest of the dwarf galaxies next to the Milky Way can be used to learn more about the early universe", – says Dr. Alice Deason.