A map of galaxies in the local universe as seen by the Sloan Digital Sky Survey which the researchers utilized to evaluate the axion theory. Each dot is the position of a galaxy and the Earth beings in the middle of the map. Credit: Sloan Digital Sky Survey
” If verified with future telescope observations and lab experiments, finding axion dark matter would be among the most substantial discoveries of this century,” states lead author Keir Rogers, Dunlap Fellow at the Dunlap Institute for Astronomy & & Astrophysics in the Faculty of Arts & & Science at the University of Toronto. “At the very same time, our outcomes recommend an explanation for why deep space is less clumpy than we thought, an observation that has actually become progressively clear over the last years or two, and presently leaves our theory of deep space unpredictable.”
In shaping the universe, gravity develops a vast cobweb-like structure of filaments connecting galaxies and clusters of galaxies together along undetectable bridges numerous countless light-years long. This is understood as the cosmic web. Credit: Volker Springel (Max Planck Institute for Astrophysics) et al
. Dark matter, comprising 85 percent of the universes mass, is undetectable because it does not connect with light. Scientists study its gravitational results on noticeable matter to understand how it is distributed in deep space.
A leading theory proposes that dark matter is made from axions, explained in quantum mechanics as “fuzzy” due to their wave-like behavior. Unlike discrete point-like particles, axions can have wavelengths larger than whole galaxies. This fuzziness influences the formation and distribution of dark matter, potentially explaining why the universe is less clumpy than anticipated in a universe without axions.
A computer simulation of a section of deep space with and without axions showing how the dark matter cosmic web structure is less clumpy if consisting of axions. For scale, the Milky Way galaxy would sit inside one of the little green dots that are called halos. Credit: Alexander Spencer London/Alex Laguë
This absence of clumpiness has been observed in big galaxy surveys, challenging the other dominating theory that dark matter consists only of heavy, weakly connecting sub-atomic particles called WIMPs. Regardless of experiments like the Large Hadron Collider, no proof supporting the presence of WIMPs has been discovered.
Keir Rogers, lead author of the research study and Dunlap Fellow at the Dunlap Institute for Astronomy & & Astrophysics. Credit: Courtesy Keir Rogers
” In science, its when concepts break down that brand-new discoveries are made and olden problems are fixed,” says Rogers.
For the study, the research group– led by Rogers and consisting of members of associate teacher Renée Hložeks research group at the Dunlap Institute, as well as from the University of Pennsylvania, Institute for Advanced Study, Columbia University and Kings College London– evaluated observations of relic light from the Big Bang, referred to as the Cosmic Microwave Background (CMB), acquired from the Planck 2018, Atacama Cosmology Telescope and South Pole Telescope surveys. The scientists compared these CMB information with galaxy clustering information from the Baryon Oscillation Spectroscopic Survey (BOSS), which maps the positions of around a million galaxies in the nearby universe. By studying the circulation of galaxies, which mirrors the habits of dark matter under gravitational forces, they measured fluctuations in the amount of matter throughout deep space and verified its reduced clumpiness compared to forecasts.
The scientists then performed computer simulations to anticipate the look of relic light and the circulation of galaxies in a universe with long dark matter waves. These estimations lined up with CMB data from the Big Bang and galaxy clustering information, supporting the concept that fuzzy axions might represent the clumpiness issue.
Future research study will include large-scale studies to map countless galaxies and supply accurate measurements of clumpiness, consisting of observations over the next decade with the Rubin Observatory. The researchers want to compare their theory to direct observations of dark matter through gravitational lensing, an impact where dark matter clumpiness is measured by just how much it flexes the light from far-off galaxies, comparable to a giant magnifying glass. They likewise prepare to investigate how galaxies expel gas into area and how this affects the dark matter distribution to further validate their outcomes.
Comprehending the nature of dark matter is one of the most pressing fundamental questions and essential to understanding the origin and future of deep space.
Currently, researchers do not have a single theory that at the same time describes gravity and quantum mechanics– a theory of everything. The most popular theory of everything over the last couple of decades is string theory, which posits another level below the quantum level, where whatever is made of string-like excitations of energy. According to Rogers, spotting a fuzzy axion particle might be a tip that the string theory of everything is correct.
” We have the tools now that could allow us to finally understand something experimentally about the century-old mystery of dark matter, even in the next decade or two– and that might offer us tips to answers about even bigger theoretical concerns,” says Rogers. “The hope is that the confusing aspects of deep space are solvable.”
Referral: “Ultra-light axions and the S8 stress: joint restrictions from the cosmic microwave background and galaxy clustering” by Keir K. Rogers, Renée Hložek, Alex Laguë, Mikhail M. Ivanov, Oliver H.E. Philcox, Giovanni Cabass, Kazuyuki Akitsu and David J.E. Marsh, 14 June 2023, Journal of Cosmology and Astroparticle Physics.DOI: 10.1088/ 1475-7516/2023/ 06/023.
National Aeronautics and Space Administration, Natural Sciences and Engineering Research Council of Canada, David Dunlap family and University of Toronto, Connaught Fund.
If consisting of axions, a computer simulation of an area of the universe with and without axions showing how the dark matter cosmic web structure is less clumpy. For scale, the Milky Way galaxy would sit inside one of the little green dots that are called halos. Credit: Alexander Spencer London/Alex Laguë.
Researchers propose in a brand-new research study that deep spaces lack of clumpiness recommends dark matter is made up of hypothetical, ultra-light particles called axions. If confirmed, this could have broad ramifications for our understanding of deep space and could even offer assistance for string theory.
In a research study published on June 14 in the Journal of Cosmology and Astroparticle Physics, scientists at the University of Toronto reveal a theoretical development that may explain both the nature of unnoticeable dark matter and the large-scale structure of the universe referred to as the cosmic web. The result establishes a brand-new link in between these two longstanding problems in astronomy, opening brand-new possibilities for understanding the cosmos.
The research study suggests that the “clumpiness issue,” which fixates the suddenly even circulation of matter on large scales throughout the universes, may be a sign that dark matter is composed of theoretical, ultra-light particles called axions. The ramifications of proving the existence of hard-to-detect axions extend beyond understanding dark matter and might attend to essential concerns about the nature of deep space itself.
A computer simulation of a section of the universe with and without axions revealing how the dark matter cosmic web structure is less clumpy if containing axions. Dark matter, making up 85 percent of the universes mass, is invisible due to the fact that it does not communicate with light. A computer simulation of an area of the universe with and without axions showing how the dark matter cosmic web structure is less clumpy if containing axions. By studying the distribution of galaxies, which mirrors the behavior of dark matter under gravitational forces, they measured fluctuations in the quantity of matter throughout the universe and confirmed its reduced clumpiness compared to forecasts.
The scientists hope to compare their theory to direct observations of dark matter through gravitational lensing, a result where dark matter clumpiness is determined by how much it bends the light from remote galaxies, akin to a huge magnifying glass.
