In the 1930s, astronomer Fritz Zwicky noted that galaxies moved faster than expected for their visible mass, suggesting an unseen matter now known as dark matter. Since then, dark matter remained unobserved except through its gravitational effect on visible matter.
Researchers have targeted areas dense in dark matter to find signals predicted by theoretical models. A leading hypothesis hol Tokyo, Japan (SPX) Nov 26, 2025
In the 1930s, astronomer Fritz Zwicky noted that galaxies moved faster than expected for their visible mass, suggesting an unseen matter now known as dark matter. Since then, dark matter remained unobserved except through its gravitational effect on visible matter.
Researchers have targeted areas dense in dark matter to find signals predicted by theoretical models. A leading hypothesis holds that dark matter consists of weakly interacting massive particles, or WIMPs. If two WIMPs collide, it is theorized they annihilate, producing gamma-ray photons measurable by telescopes.
Using new data from NASA's Fermi Gamma-ray Space Telescope, Professor Tomonori Totani at the University of Tokyo identified gamma rays extending in a halo-like structure from the center of the Milky Way. The measured gamma-ray energy reached 20 gigaelectronvolts. This emission closely aligns with the shape expected from a dark matter halo.
Totani found that the measured energy spectrum of the gamma rays matched that expected from the annihilation of WIMPs about 500 times heavier than a proton, and the rate of these annihilations corresponded with prior theoretical predictions.
Known astronomical phenomena do not readily explain these gamma ray emissions, leading Totani to describe the data as a strong indication that the emission originates from dark matter.
"If this is correct, to the extent of my knowledge, it would mark the first time humanity has 'seen' dark matter. And it turns out that dark matter is a new particle not included in the current standard model of particle physics. This signifies a major development in astronomy and physics," said Totani.
Totani emphasized the importance of independent verification and additional evidence, such as detecting similar gamma-ray energy from other regions with high dark matter concentrations. If confirmed, these observations would provide the strongest indication to date of gamma rays arising from dark matter particles.
Research Report:20 GeV halo-like excess of the Galactic diffuse emission and implications for dark matter annihilation
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