Astronomers said goodbye with the hope to explain the mysterious x-rays from space by the decay of dark matter particles. Both mysteries – the nature of dark matter and strange source of x-rays – remain unsolved. This was concluded in a scientific paper published in the journal Science.
“News.Science” (nauka.vesti.ru) told in detail why scientists believe in the existence of dark matter and why the majority of experts believes that for the most part it is not composed of known particles such as protons and electrons.
what, then, is it? This question has no exact answer. Scientists have put forward different hypotheses. On the Ground, working a few detectors designed to detect dark matter particles, but so far these searches have not brought result.
In 2014, the scientific world was excited by the news, it would seem that shed light on the nature of this substance. We are talking about the discovery of x-ray radiation with quantum energy-3.5 kiloelectron-volt (Kev) emanating from distant galaxies.
there are No known astrophysicists objects and processes do not generate x-rays with such a spectral line. Itself suggests a tempting hypothesis that these photons are emitted by dark matter.
According to one hypothesis, the latter consists of sterile neutrinos. This hypothetical particle which will eventually decay into ordinary neutrinos by emitting electromagnetic radiation. Sterile neutrinos with an energy of 7 Kev would give the x-ray quanta with energies of just 3.5 Kev. In addition, the intensity of the radiation well matched to the amount of dark matter in the observed galaxy cluster.
it would Seem that the scientists killed three birds with one stone: to clarify the nature of dark matter, explained the origin of x-rays with an energy of 3.5 Kev and proved the existence of sterile neutrinos. But even the most beautiful theories require many independent facts for its confirmation.
Nature of dark matter still remains a mystery to scientists.Illustration Pixabay.
Researchers from three scientific centers of the United States decided to test this hypothesis. They just talked. Dark matter is present in all galaxies, including ours. In fact, the milky Way is immersed in a spherical cloud of this substance. Wherever we look, we see through the plume of invisible dark matter.
If it emits x-rays, those should always be captured in the x-ray telescopes. Another thing is that the radiation must be pretty weak, not conspicuous. Thus, to trace him in these orbiting observatories, it is necessary to search.
astronomers took up the search. They analyzed images taken by the XMM-Newton telescope in 20 years. In total the data covers about a year of pure time observations. The researchers eliminated the signal, which was sent to the instrument, and was looking for the radiation emitted by virtually empty space (or rather, filling his dark matter).
the result has been unprecedented accuracy tested the hypothesis that dark matter consists of sterile neutrinos, the decay of which generates radiation with an energy of 3.5 Kev. Alas, it has not been confirmed.
However, the hypothesis that dark matter consists of sterile neutrinos, too early to dismiss. It can be assumed that the particles fall less than previously thought, and emit quanta of different energy. The latter, by the way, you can check, because the proposed method is suitable for searching for emission from dark matter on different wavelengths.
One of this can be said with certainty: the assumption that dark matter consists of sterile neutrinos, the decay of which generates radiation with an energy of 3.5 Kev, have failed.
“Our results do not imply that dark matter is sterile neutrinos. But they mean that, contrary to what was announced in 2014, to date, no experimental evidence pointing to their (sterile neutrinos – approx. ed.) the existence of” – sums up the head of the research group Safdi Benjamin (Benjamin Safdi) from the University of Michigan.
However, the mystery of the lines of the 3.5 Kev is still here. Astronomers still don’t know which process produces such x-rays. And we can not exclude that the reason dark matter, even if it does not consist of sterile neutrinos. So, another research group suggests that dark matter in the galaxy cluster Perseus absorbs radiation emitted by the surroundings of a supermassive black hole, and pereslushal it in the form of quanta with energy of 3.5 Kev.
By the way, before “News.Science” (nauka.vesti.ru) wrote about the fact that the sterile neutrino can be the answer to the question of why matter in the Universe than antimatter.