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The center of the Milky Way galaxy mysteriously shines, and of course there is a whole host of stars, as well as a black hole 4 million times the mass of the sun.
But, as light is removed from all of this, the area remains inundated with superfluous gamma rays.
It’s called the Galactic Center GeV Excess (GCE), and scientists have been puzzled since its discovery by physicists Lisa Godineau and Dan Hopper, in 2009. In data from NASA’s Fermi Telescope, they found excess radiation gamma – one of the most energetic lights in the world. universe.
Physicist Mattia de Moreau, from the National Institute of Nuclear Physics in Italy, said his analysis points to dark matter as the culprit for GCE (this was first presented as an explanation by Godino and Huber).
(NASA Goddard; A. Mellinger, CMU; T. Linden, Univ. Of Chicago)
It is known that there is a mysterious mass responsible for the effects of gravity, which cannot be explained by things that we can discover directly – natural matter like stars, dust, gases and galaxies.
For example, galaxies spin much faster than they should if their gravity is affected by natural matter. The gravitational lens – the bending of space-time around massive objects – is much stronger than it should be. Anything that creates that extra sparkle is beyond our ability to reveal it directly.
And we only know about dark matter from the effect of gravity on other objects, and there’s a lot of it out there. Almost 80% of all matter in the universe is dark matter, although we can’t see a piece of it.
The researchers suggested that if certain dark matter particles called WIMPS (Massive Low Interaction Particles) and their antiparticles collided, they would annihilate and explode in a shower of other particles, including gamma photons. This explanation, they said, fits the data surprisingly. Other physicists were not convinced, with one even describing the explanation as “flawed”.
And in 2018, another team of scientists suggested that very old dead stars called pulsars could cause an overflow. This makes sense, because the galactic center is so crowded, dusty, and bustling – it would be very easy to miss one or more stars.
Recent studies have also revealed that the GCE distribution is not smooth – as one would expect from dark matter annihilation – but rather lumpy and speckled, which the pulsar team interpreted to be consistent with. point sources, such as stars.
Then another team came and decided that thin gamma radiation could be produced by dark matter, which brought it back to the table. However, more and more researchers have created a series of complete models of the galactic center with annihilation of dark matter using an array of masses in the most studied systems. And they found that WIMPs were unlikely to be the cause of the ECG.
De Mauro’s study compares data from the Fermi Telescope over the past 11 years, with measurements of other astronomical anomalies recorded by Pamela’s cosmic ray detector onboard Resurs-DK No.1 and the alpha magnetic spectrometer aboard the International Space Station.
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In particular, the study uses the larger Fermi data set, collected over the past year, and reduces the uncertainty caused by background radiation. De Mauro said this provides information about the spatial distribution of GCE, which could help rule out different interpretations.
He explained, “If, for example, the excess is caused by the interaction between cosmic rays and atoms, then we would expect to observe their greater spatial distribution at lower energies, and their lower propagation at higher energies. due to the scattering of cosmic particles My study, on the other hand, confirms how the distribution is: “The spatial increase does not change with energy.”
This, he said, had not been observed before and could be explained by dark matter, as we believe dark matter particles should have similar energies.
He continued, “The analysis clearly shows that the increase in gamma rays is concentrated in the center of the galaxy, which is exactly what one would expect to find in the heart of the Milky Way if dark matter was in fact a new type of particle. . “
In a second pre-print article, de Moreau and his colleague Martin Wolfgang Winkler of Stockholm University in Sweden attempted to search for excess gamma rays in nearby dwarf globular galaxies. They found nothing, but this empty discovery allowed restrictions to be placed on the mass of the dark matter particle. They said these limitations are compatible with GCE.
Does this mean that dark matter is the source of CME? No – at the same time, we can’t say that dark matter doesn’t cause it either. And basically everything is just as confusing as it was before, and we’re going to need some great science (and a lot of notes, probably) to get to the bottom of this.
De Mauro’s research has been published in a journal Physical examination DThe second sheet is available on arXiv.
Source: ScienceAlert
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