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Journalism of Courage
A small but distinctive X-ray signal detected from the Milky Way galaxy by NASA’s Chandra satellite may help prove the existence of dark matter, scientists have claimed. Researchers, including those from Massachusetts Institute of Technology (MIT) and Yale Centre for Astronomy and Astrophysics in the US, analysed the energy spectrum of X-rays.
They found more X-ray photons with a particular energy than would be expected if they were produced only by familiar processes. Those photons could in fact have been generated by the decay of dark matter particles, say the researchers. This is not the first time that scientists have seen extra photons with an energy of about 3,500 electronvolts in the spectra recorded by X-ray satellites.
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However, previously it was not clear whether the bump, or line, created by the photons in the otherwise smooth spectrum was merely an instrumental artefact, said Kevork Abazajian, from the University of California, Irvine. Scientists reckon that dark matter makes up more than 80 per cent of all the mass in the universe.
As its name suggests, it gives off no light, but reveals its presence through the gravitational tug it exerts on stars within galaxies. For years, physicists have been trying to detect particles of dark matter directly by intercepting them using instruments on Earth.
The latest research, carried out by Nico Cappelluti at Yale, targets relatively light particles of dark matter, ‘BBC News’ reported. Esra Bulbul of the Kavli Institute for Astrophysics and Space Research at the MIT was the first scientist to spot an anomalous line at 3.5 keV, when looking at the X-ray spectra of large numbers of galaxy clusters in 2014.
