In the midst of our exploration for cosmic evidence of the existence of dark matter, the viewer may see us as drunken people searching for their lost keys under lampposts, where the light is at its brightest, and lampposts in our case are regions of space teeming with galaxies and galaxy clusters, which are thought to be Embedded in thick clouds or “halos” of dark matter, but what if our eyes were instead focused on cosmic voids, the vast expanses of almost completely empty space? In a draft of a new, as yet unpublished study, a team of three scientists says that although overall dark matter signals from such cosmic regions may be weaker, they may be considered less contaminated by astrophysical sources and thus may be easier to detect.
“This is a new idea, and it is not just an idea;
It is believed that dark matter constitutes more than 80% of the matter of the universe, and this estimate depends mainly on what we see of the gravitational effects of that perplexing matter on the gases, dust, stars, and galaxies that make up ordinary matter. The dark matter that holds galaxies together, those galaxies disintegrated long ago due to the speed of their rotation.
Most physicists have best speculated that dark matter is made up of so-called weakly interacting massive particles (WIMPs), but direct evidence remains elusive, despite decades of searching for it in particle accelerators and ultra-sensitive detection equipment buried on They go deep underground to avoid as much signals from cosmic rays and other sources as possible, but these particles are still the most likely model for what dark matter is, says one of the researchers involved in the study, Nicolao Furningo at the University of Turin in Italy.
According to most models based on weakly reactive massive particles, if these particles are as heavy as expected—from a few gigaelectronvolts (GeV) to a few teraelectronvolts (TeV), a gigaelectronvolt modifies into a mass of Almost a proton – they must eventually decay or collide with each other and annihilate, in both cases producing gamma rays, Furningo comments on this: “If dark matter emits gamma rays, the signal must exist.”
Existing gamma-ray observatories, notably NASA’s Fermi Observatory with its Wide Range Telescope (LAT), are picking up what looks like a scattered “background” of gamma rays across the entire sky. Known astrophysical sources, such as pulsars and supermassive black holes swallowing matter, are not evenly distributed across the sky, which is consistent with astrophysicists’ predictions of dark matter emissions and astrophysical sources so small that even Fermi observatory with its telescope With regard to dark matter, the gamma-ray glow from weakly interacting massive particles that dissolve and annihilate must be associated with the massive cosmic structure, being brighter when emitted from densely packed areas of matter and faint When emitted from empty areas, and the first studies in this field indicate this association, but they have often avoided empty areas and focused on – rather than That’s – on bright regions full of galaxies and galaxy clusters, and to see if signals from voids are easier to detect than those from denser regions, scientists set up computer models of how signals from both types of cosmic structures are likely to come from both types of cosmic structures. She points out that the total emission of gamma rays from dark matter and normal matter in vacant regions is much weaker than that emitted from densely packed regions, but this weakness is an advantage rather than a defect, as the relatively lack of normal matter ensures that there are few astrophysical sources that would otherwise block gamma rays emitted by dark matter. “This is a trade-off between two cases: that the measured signal is stronger and more polluted versus weaker and more pure,” says Forningo. The study he conducted with colleagues was sent to the Journal of Cosmology and Astroparticle Physics. Journal of Cosmology and Astroparticle Physics in order to publish it.
The team also came to a surprising conclusion: that most of the gamma rays emitted by dark matter in these empty regions must be caused by the decay of particles rather than their annihilation. Interaction in this cosmic vacuum is limited, but the decay of particles is inevitable, regardless of the intensity of their spread. less dense.
Because this technique has a better signal-to-noise ratio, and favors the detection of gamma rays emitted by decaying particles, it may provide us with revealing new insights into the properties of dark matter, which we would not have obtained if we had studied only gamma rays from regions overcrowded alone, according to Hammus; For example, the higher the average lifespan of a dark matter particle, the less decay occurs in a given time or space, so we say that while such a faint signal would normally not be detected, it would not necessarily be the case in empty regions. : “Because the signal-to-background-noise ratio is higher, we can delve further into the possible possibilities.”
With cautious optimism, New York University astrophysicist Anthony Bolen, who was not involved in the study, looks forward to experiments in the near future to validate the study’s main ideas. It is planned to begin later this decade large-scale observations of the cosmic structure using next-generation equipment such as the European Space Agency’s Euclid Telescope, the Nancy Grace Roman Space Telescope and the Vera C Observatory. “As these observations begin, we are expected to have a huge amount of data, and the more galaxies we can find, the more accurately we can locate the cosmic voids,” says Pollen. This will be useful for this type of study, and in the next few years we may see something similar presented as proof of the feasibility of the idea.”
Today, proof-of-concept may be limited by resorting to gamma-ray data collected by the Fermi telescope, which is not enough, Furningo and colleagues say, because their calculations indicate that reaching conclusive detections will require a new generation of gamma-ray-monitoring equipment twice the size of the detector. And five times the angular resolution (the ability to distinguish between different sources in the sky) of the Fermi telescope, Forningo says, “Building a new Fermi telescope would be a great plus,” although he admits that such a detector is a bit of a fantasy at the moment. This did not prevent the team from choosing a suitable Italian name for the hoped-for detector, so they named it Fermissimo.