Mysterious ‘glow’ from the centre of the Milky Way could be explained at last

Rob Waugh
·2 min read
The galactic core area of the Milky Way over Maskinonge Pond in Waterton Lakes National Park, Alberta. Jupiter is the bright object at left, with Saturn dimmer to the left (east) of Jupiter. In the summer of 2020 the two planets were close together in the summer sky. Jupiter provides the glitter path on the water. Antares and Scorpius are to the right. Sagittarius is at centre. This was July 13-14, 2020. As is typical of Waterton, it was windy enough tonight that there was no sharp reflection of the stars and Milky Way in the water. This is a stack of 12 exposures for the ground, mean combined to smooth noise in the dark foreground, with the sky from one exposure, all untracked for 30 seconds at f/2 with the Sigma 20mm lens on the Canon EOS Ra camera at ISO 3200. Stacked and blended in Photoshop. (Photo by: Alan Dyer/VW PICS/Universal Images Group via Getty Images)
The ‘glow’ is in the form of gamma radiation and was spotted by scientists in data from NASA’s Fermi space telescope in 2009. (VW PICS/Universal Images Group via Getty Images)

The centre of our own Milky Way galaxy is emitting a mysterious glow which scientists have puzzled over for a decade - but a new paper suggests a culprit.

The ‘glow’ is in the form of gamma radiation and was spotted by scientists in data from NASA’s Fermi space telescope in 2009.

It’s known as the Galactic Center GeV Excess (GCE) – and new data suggests it’s created by ‘dark matter’, a theoretical form of matter which could make up 80% of the matter in the universe.

Researchers analysed data collected by the Fermi Large Area Telescope (LAT) collected over 11 years, along with data from the Pamela detector and by the Alpha Magnetic Spectrometer experiment (AMS-02) aboard the International Space Station.

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The analysis suggests that the ‘glow’ is caused by dark matter, which is thought to make up 80% of all the matter in the universe.

The researchers believe that the ‘glow’ is caused by a new and undetected sort of particle in the Galactic centre.

So far, we have only been able to detect dark matter via its gravitational effects on other objects.

Mattia Di Mauro, of the National Institute for Nuclear Physics, said: "The analysis methodology used, has provided very relevant information about the spatial distribution of excess gamma radiation, which can explain what generates the excess of high-energy photons in the galactic center.”

Di Mauro added that the data allows scientists to discount several previous theories.

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“If the excess was, for example, caused by the interaction between cosmic rays and atoms, we would expect to observe its greater spatial distribution at lower energies and its lower diffusion at higher energies due to the propagations of cosmic particles. My study, on the other hand, underlines how spatial distribution of the excess does not change as a function of energy," said Di Mauro. 

“This aspect had never been observed before and could be explained by dark matter presence dark matter interpretation. This is because we think the particles composing the dark matter halo should have similar energies.

“The analysis clearly shows that the excess of gamma rays is concentrated in the galactic center, exactly what we would expect to find in the heart of the Milky Way if dark matter is in fact a new kind of particle."

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