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In dwarf galaxies, dark matter is a thousand times more than usual
Astronomers from the University of Texas at Austin is believed to have found the answer to question 20-year-old: a mysterious cosmic dark matter is distributed in small galaxies? Scientists have found that the distribution of, on average, follows a simple law of diminishing density from the center of the galaxy, although the exact figure of distribution varies from galaxy to galaxy. The study was published in the journal Astrophysical Journal Letters.
Dark matter – this is a matter which does not emit any light, but astronomers can detect its presence by gravitational effects on other objects (stars, for example). There are lots of theories about what is made out of dark matter – the invisible particles, dead stars, etc. – But no one knows for sure. But understanding the nature of the mysterious dark matter is of the utmost importance to us as it is for the major part of matter in the universe. The only way to understand how the universe evolved to its present state – understand the role of dark matter.
Therefore, astronomers study the distribution of dark matter in galaxies and even larger scale. Dwarf galaxies, it is worth noting, form an excellent laboratory for the study of dark matter, astronomers said John Jardel and Karl Gebhardt, because they contain 1,000 times more dark matter than normal. Normal galaxies like the Milky Way, contain a total of 10 times more dark matter than normal.
In the picture above shows the Sagittarius dwarf galaxy, named for the constellation in which it can be seen from Earth, in the course of the collision and merging with our own Milky Way. Most of the astronomical research has focused specifically on the effects of a collision with this dwarf galaxy, because a huge force of gravity and tidal forces of the Milky Way dwarf galaxy torn, literally pulling in long streams of stars that flow around our own galaxy.
Over the past 20 years, astronomers observers and theorists have argued a lot about how dark matter is distributed in galaxies. Observational astronomers, using data from their telescopes have argued that the distribution of dark matter in galaxies is quite uniform. Theorists have also enlisted the support of computer modeling, argue that the dark matter density decreases from the center to the outskirts of the galaxy. This discrepancy is known as “the problem of core / cusp» (literally challenge the core and suburbs).
Jardel work is based on data as of telescopes, and computer models. The project did not start by finding out which theory is correct, but simply with the question “What is it? ‘. New models have to follow this way.
Jardel used telescopes for observing several satellite galaxies orbiting the Milky Way, including Carina, Draco, Stoves, sculptor and a sextant. The work has included many supercomputer models of each galaxy to explain the distribution of dark matter in them, using the Texas Advanced Computer Center (Texas Advanced Computing Center, TACC).
Scientists have discovered that in some galaxies dark matter density continuously decreases from the center when the other remains unchanged. Some galaxies fall into the section between the two. However, when all distributions have been analyzed, the results showed that on average, the theorists were right.
“When you look at individual galaxies,” – says Jardel – “Some of them look quite different, as you’d expect. However, when you peered at the same time in several galaxies, the differences between them tend to cancel each other. ”
This suggests that the theory of the distribution of dark matter in galaxies in general is correct, but “every galaxy develops a little differently.”
The results raise other questions: the dark matter of how normal matter interacts with the dark, and how this affects the shape of galaxies that we see.
Perhaps the next step in this research will include a more telescopic observations of galaxies, as the center and outskirts, in order to understand the distribution of dark matter even more.
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Tags: Universe , Galaxy , Dark Matter , Physics .
Just a fact, it’s more or less the only logical explanation. This may not be the matter at all, just a code name of “what’s missing” under other laws. How could a read – it’s gravitational influence, and therefore it follows, as the mass and so on. I’m not a scientist and do not pretend, but it seems to me – the dark matter does not exist, it is a fruit of imagination of scientists to plug holes in their theoriesViewing:-157
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