the distribution of matter in the Universe with background gamma radiation and found
the correlation between them. The bulk of the signal can be explained by the effect of dim
blazers, but some must be associated either with a new population of objects
unusual properties, or with a fundamentally different class of sources. Not
is possible that it represents the annihilation of dark matter particles, write
the authors in the journal Physical Review Letters.
A number of astronomical
observation shows that in addition to known substances, which consist
stars, gas clouds and galaxies in the Universe is present and the other component
nature, called dark matter. It should account for approximately
85 percent of the mass of all kinds of matter, but scientists do not yet know what she
is. According to the most popular hypotheses, dark matter consists of
particles with masses of order of the proton or more.
the device dark matter assuming that its particles can annihilate with
reaction with each other. In this case, they should turn into a couple of others.
particles, including photons of high energies. The search for such signals
continue for several years, but convincing data are still pending.
One of the Supervisory
indications for the existence of dark matter is much greater
the gravitational mass of galaxies and their clusters than can be assumed on the basis of
they contained stars. This conclusion can be derived from the curvature of rays
light from background objects passing near massive formations, —
the gravitational lensing.
At a close passage
of light rays near a massive compact object occurs much
gravitational lensing, which generates additional distorted
image source. However, this happens rarely, usually occurs
another mode — weak lensing, which slightly alters the shapes and sizes
background objects, but can be aggregated in the presence of a large
sample. Large surveys of the sky allow you to build a weak lensing map from
where it is possible to calculate the distribution of mass in the Universe.
A group of scientists with the participation of Simon Ammazzalorso (Simone Ammazzalorso) from Turin
University conducted a comparison of weak lensing maps obtained through
review DES, and
the distribution of background gamma sources, according to the space telescope “Fermi”. It turned out that the position of gravitational lenses, which primarily must meet the dark
matter, correlates with the coordinates of the high-energy light quanta. The authors
note that other authors have previously tried to find such a signal
using other data, but one group of researchers have not been able
Astronomers used data from 108 months of observation space Observatory and results of the first year
Of these “Fermi” was
removed the known sources subtracted model and the intensity of the background milky
Way. The correlation between the searched coordinates and fluxes in the gamma range
measured through lensing changes the shape of the galaxies — gravitational
shift. Signal-to-noise cross-correlation was above the five that
shows the presence of a noticeable effect
Analysis for different
the scope and ranges of energy showed that a large part of the signal is necessary at
the greatest angular scales (less than 0.3 degrees) and high energy. This
the effect is easiest to explain the presence of the background population of point sources
and hard range (steep dependence of the flux on frequency) with the index
about 1.8. More on the role of such objects fit blazey — active
the nuclei of galaxies with a small angle between the line of sight and the direction of motion of the jet from
the Central black hole.
Also, astronomers have discovered
a less statistically significant correlation on large angular scales. Below
to define its nature, scientists conducted a simulation of the expected signal from
not bright blazers, of other active galactic nuclei, galaxies with active
the star formation in galaxies and the dark matter. It turned out that from a statistical
significance of about three standard deviations in the signal present contribution
annihilation of dark matter with masses of 65 ± 25 GeV.
The authors note that
the final significance of the signal of dark matter is not very large. It is also possible,
dim that populations of high energy sources differ in the parameters
from brighter known. In this case, the estimates should
correct. However, ongoing surveys, like DES, as well as future large-scale projects, like LSST, will provide much
more data, which allows much more accurate to measure the possible contribution of dark
Previously, scientists suggested a new way to search for dark matter particles using superconducting nanowires, and also showed the incompatibility of the idea of a superfluid dark matter to the dynamics of stars in the milky Way. We also did a special test on the basic models of this component of the Universe — “What are you dark matter?”.