Dark matter — the invisible substance, the presence of which can be judged only by its gravitational effects.
The journal Physical Review Letters published a study showing that dark matter cannot consist of ultra-light particles.
It is believed that dark matter consists of heavy non-interacting with each other particles “vinow” (Weakly Interacting Massive Particles). Because wimpy” were never discovered, scientists have suggested that dark matter may have different physical properties. Opinions were divided, some believed that dark matter is a
some form of liquid. Others felt that it was heavy and, on the contrary, strongly interacting particles “simpy”. Third theory became extremely light particles “axions”, which hundreds of thousands of times lighter than electrons.
Manuel Mayer from the University of Stockholm (Sweden) with colleagues have found empirical evidence that in fact one of the theories does not correspond to reality, and the axions do not exist. To such conclusion scientists came during a six-year observations of fluctuations in the spectrum of galaxies. If axions existed, they would interact with the photons when they pass through a strong magnetic field, which cannot be ignored near the black holes and magnetars. Signature of the interaction would be traces in the galactic spectrum, characterized by a significant decrease in the intensity of gamma radiation. In addition, with the existence of axions, the universe would not be as transparent as the result of the interaction of axions with particles of light would be formed of a pair of gamma photons, covering the gamma-rays from stellar associations.
Collaboration “Fermi” tried to find prints of this “gamma-echo” dark matter, by observing the galaxies in the cluster of Perseus. The researchers found that in the study area there are no hints about the existence of anything, so affect the behavior of photons. Based on this, conclusions were drawn about what is really axions do not exist or their weight much more than expected. Also consider the scenario that dark matter consists not only of axions. At the moment, the scientific community has no tool to confirm or refute this idea.