dimanche 14 décembre 2014

The signal of dark matter could have been detected







Ecole Polytechnique Fédérale de Lausanne (EPFL) logo.

December 14, 2014

The signal of a dark matter particle could have been detected. EPFL researchers have identified an atypical photon emission in X-rays from celestial objects. If this discovery is confirmed, "a new era" would open in astronomy, said Thursday the High School.

The researchers analyzed the X-rays emitted by two celestial bodies: the Perseus cluster of galaxies and the Andromeda galaxy. They have thus noticed an error that put their flea in the ear, although the possibility of errors can not be completely excluded.


Image above: Chandra X-ray Observatory observations of the central regions of the Perseus galaxy cluster. Image is 284 arcsec across. RA 03h 19m 47.60s Dec +41° 30' 37.00" in Perseus. Observation dates: 13 pointings between August 8, 2002 and October 20, 2004. Color code: Energy (Red 0.3-1.2 keV, Green 1.2-2 keV, Blue 2-7 keV). Instrument: ACIS. Image Credits: NASA/CXC/IoA/A.Fabian et al.

The signal is manifested by a low emission and non-typical photon can not be traced to any known material. In addition, "the distribution of the signal within the galaxy corresponds exactly to that in which we expect to find dark matter, more concentrated and intense in the center of the objects, weaker and diffuse around the edges," said Oleg Ruchayskiy, one of the researchers quoted in the release.


Image above: Andromeda galaxy (M31) seen by Hubble Space Telescope. Image Credits: NASA/ESA.

To test the hypothesis, "we then conducted surveys within our galaxy, the Milky Way, and made the same observations," adds his colleague Alexey Boyarsky. The discovery of the two employees of the Physics Laboratory particles and cosmology (CFPA) at EPFL in Lausanne will be published Monday in "Physical Review Letters".

80% of the universe

The detected signal is due to the emission of a photon resulting from the destruction of a hypothetical particle, for example a sterile neutrino. If these developments continue, "a new era" opens for astronomy, according to Oleg Ruchayskiy. Thanks to new tools, researchers should be able to understand what dark matter is made.

For the record, physicists are faced with a mystery when studying the dynamics of celestial bodies. Their equations do not take if they are based only on visible matter. The observables do not explain the rotation of objects and gravitational forces.


Image above: The 3D distribution of dark matter obtained from a large numerical simulation and Hubble observations, dark matter it would be at least 80% of the universe. Image Credits: NASA/ESA.

Faced with this lack of understanding, physicists have deduced the existence of invisible matter that does not interact with light, but gravity acts on the set. They called dark matter and think it would be at least 80% of the universe.

For more information about Ecole Polytechnique Fédérale de Lausanne (EPFL), visit: http://www.epfl.ch/index.en.html

Images (mentioned), Text, Credits: ATS / Orbiter.ch Aerospace.

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