Wednesday, September 26, 2012
NASA showed massive halo of hot gas surrounding our galaxy
In the U.S., NASA scientists have once again reminded people how big the universe - to show how small our Milky Way galaxy, if it is placed in the newly discovered halo - a cloud of hot gas that extends for hundreds of thousands of light years.
When is the estimated mass of the halo is comparable to the mass of all the stars in the galaxy - is able to detect by X-ray Observatory "Chandra". Estimate the size - is important because it can explain the problem of "missing baryons" - that is, the particles that make up 99.9% of the mass of all the atoms in the universe.
Scientists believe that the baryonic matter in the universe there is a very long time - now, when her age was only a few billion years, and it accounts for one-sixth of the mass and density of dark matter.
At least half of the dark matter halo of the galaxy in the form of baryons owes its origin to the contribution of low-mass stars and brown dwarfs. What is in the second half of the baryonic component of dark matter and the nature of the components of the non-baryonic dark matter remains a mystery.
NASA believe that beyond the Milky Way, there are eight superhot and dense clouds of elements where there are oxygen ions, which are hundreds of times hotter than the surface of the Sun and from 1 to 2.5 million Kelvin. It goes halo colder - from 100,000 to 1 million Kelvin.
Note, in 2008 an international team of astronomers from the Netherlands, Germany and other countries used the data obtained orbiting X-ray observatory XMM-Newton («Newton") of the European Space Agency, in order to find the part of the dark matter in the universe. This is not about the so-called "dark" matter, and an ordinary (baryonic) matter consisting of atoms - nucleons, electrons - and other particles already known to science that are simply not visible to ordinary telescopes.
Almost all of the matter in the universe is collected in giant structures - a kind of invisible network, in the most dense nodes of which, like spiders, "sit" galaxy clusters - the largest structural units of the world. Astronomers have long suspected that stretched from one site to the "thread" of the network laid gas having a low density and high temperature (105-107 degrees Kelvin), which allows them to emit X-rays. Unfortunately, the large sparse gas is still almost insurmountable obstacle to its discovery.
It should also be said that in a recent study, a team of five astronomers used the data "Chandra" and "Newton" and space observatory "Suzaku" tried to set limits on the temperature, volume and mass of the hot gas halo. Studies have shown the presence of hot gas with a temperature of more than 1 million Kelvin.
This new study shows hot gas halo enveloping the Milky Way is much more massive than the warm halo gas.
"We know about the gas clouds around galaxies, and we know how hot it can be," said Ange Gupta, one of the authors of the study, adding that another interesting question - how big halo and how it massively. It turned out that quite large - from 10 to 60 billion solar masses, reports Daily Mail.
"Our work shows that under reasonable parameters and reasonable assumptions, observations," Chandra "show the huge amount of hot gas around the Milky Way" - added Mathur co-Smith of the University of Ohio.
"In any case, its mass is very large. Estimated weight is dependent on such factors as the amount of oxygen to hydrogen - they dominate in the gas, "- he added.
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