Posted on February 16, 2019
Astronomers spent decades looking for something that sounds like it would be difficult to miss: about a third of the "normal", "Barion, matter in the universe" . NASA's newest X-ray observatory, CHANDRA, may have helped them find this elusive space of missing substance. helium and other elements ̵
The problem is that when astronomers make up the mass of all normal matter in the modern universe, about a third of it can not be found. (This missing matter differs from the still mysterious dark matter.)
Dark matter – "came out from the sea to the great bang" (feature of the day off)
A new version of the Hubble deep-field image is shown above. In dark gray, you can see the new light that was found around galaxies in this field. This light corresponds to the brightness of more than one hundred billion suns. She has taken researchers from Astrofísica de Canarias for almost three years to create the deepest image of the universe ever taken from outer space by restoring a large amount of "lost" light around the largest galaxies in the iconic ultra-deep field of the Hubble.
Mysterious bright flashes of radio – "reveals the missing case of the universe"
One idea is that the missing mass is collected in giant threads or threads of warm (temperature less than 100 000 Kelvin) and hot (temperature over 100 000 Kelvin) gas in the intergalactic space. These threads are known by astronomers as "hot hot intergalactic media" or WHIM. They are invisible to optical light telescopes, but part of the warm gas in the threads was detected in ultraviolet light.
Using new technology, researchers found new and significant evidence for the WHIM hot component based on Chandra and other telescopes.
"If we find this missing mass, we can solve one of the greatest puzzles in astrophysics," said Orshova Kovach of the Center for Astrophysics | Harvard & Smithsonian (CfA) in Cambridge, Massachusetts. "Where did the universe seize so much of its substance that makes such things as stars and planets and us?"
Astronomers used Chandra to search and study the threads of warm gas lying along the way to a quasar, a vivid source of X-rays powered by a rapidly growing supermassive black hole. This quasar is located about 3.5 billion light years from Earth. If the WHIM hot gas component is affiliated with these threads, some of the quasar X-rays will be absorbed by hot gas. They were looking for a signature of the hot gas that was captured in X-ray light of a quasar discovered by Chandra.
One of the problems of this method is that the absorption signal WHIM is weak compared to the total number of X-rays coming from the quasar.
When searching for the entire spectrum of X-rays at different wavelengths, it is difficult to distinguish such weak absorption characteristics – real WHIM signals – from random fluctuations. parts of the X-ray light spectrum, reducing the likelihood of false positives. They did this by first detecting galaxies near the quasar line, which are at the same distance from the Earth as the areas of warm gas, detected from the data of ultraviolet radiation. With this technique, they found 17 possible threads between the quasar and us, and got their distances.
"Heresy!" – A controversial alternative to the theory of severity of the general theory of relativity – does not require the existence of dark matter. ]
Because of the expansion of the universe that extracts light during a trip, any absorption of X-rays by a substance in these threads will be shifted to more red wavelengths. The sum of shifts depends on known distances to the filament, so the team knew where to look in the spectrum for absorption from WHIM.
"Our technique is fundamentally similar to how one can conduct an efficient search for animals in the vast plain of Africa," said Agos Bogdan, co-author of the CfA. "We know that animals need to drink, so it makes sense to first look around the irrigation holes".
By narrowing their search, researchers also had to overcome the problem of weakness of X-ray absorption. Thus, they increased the signal by adding 17-thread spectra, converting observations to 5.5 days in the equivalent of data for almost 100 days. With this technique, they discovered oxygen with characteristics that indicate that it is in a gas with a temperature of about one million degrees Kelvin. Researchers report that they can take into account the total amount of missing substance. At least in this particular case there is no question hiding in WHIM
"We were delighted with the fact that we were able to track down part of this absent case," said co-author Randall Smith, also CfA. "In the future, we can apply the same method to other quasar data to confirm that this ancient mystery was finally broken."
Daily galaxy through the Chandra X-ray center