All articles tagged with #large scale structure
A claimed anisotropy in the DESI galaxy survey is shown to be an artifact from not accounting for redshift-space distortions. When comoving distances are used and distortions corrected, the data align with a homogeneous, isotropic universe, reaffirming the cosmological principle and the standard model of cosmology.
Using the COSMOS-Web program, the James Webb Space Telescope has produced the largest-ever 3D map of the universe, charting about 164,000 galaxies over a 255-hour survey to reveal the cosmic web’s skeleton from the present back to when the universe was under 1 billion years old. The map shows dense regions fostering early galaxy growth and, later, environmental quenching in massive galaxies—likely driven by massive dark matter halos and feedback from supermassive black holes—providing new insight into how the large-scale structure of the cosmos evolved. The COSMOS-Web galaxy catalog is publicly available for researchers.
Two gigantic structures—the Giant Arc and the Big Ring—share the same redshift (~9.2 billion light-years) and lie about 12 degrees apart in the sky, inferred from Mg II absorption in quasar spectra rather than direct imaging. If real and physically connected, they challenge the cosmological principle of large-scale homogeneity under Lambda-CDM and would require explanations for such vast, ordered patterns; however, statistics and potential artefacts are debated, and future surveys and simulations will test their persistence and implications for cosmology.
New DESI-based analysis finds directional patterns in the galaxy distribution that persist across billions of light-years, suggesting the universe may not be perfectly uniform on the largest scales. If confirmed, this challenges the cosmological principle and could force revisions to the standard Lambda-CDM model, including possibilities of more complex dark-matter interactions or larger-scale inhomogeneities. The observed patterns are stronger than those produced by simulations, underscoring the need for further data from DESI, Euclid and other surveys to verify the result and guide new theories of cosmic structure.
Astronomers led by Alexia Lopez report two ultra-large galaxy structures—the 1.3-billion-light-year Big Ring and the nearby Giant Arc—challenging standard cosmology and the Cosmological Principle; they are not BAOs, and could hint at exotic explanations like conformal cyclic cosmology or cosmic strings; light from these structures has traveled about 6.9 billion years, and more such discoveries are needed to understand their origin.
New DESI data analysis finds galaxy distributions forming structures that extend to gigaparsec scales, appearing larger and more coherent than predicted by the standard Lambda-CDM cosmology and indicating persistent directional patterns. While this suggests a potential gap between theory and observation, scientists say there’s no agreed modification to ΛCDM yet; upcoming DESI releases and future surveys from Euclid and the Vera C. Rubin Observatory will help test these surprising findings.
Using JWST’s COSMOS-Web survey, astronomers mapped about 164,000 galaxies over a 255‑hour program to produce the largest, most detailed view of the cosmic web. The map shows how dense regions foster early galaxy growth and eventually quench star formation, revealing the large-scale structure of the universe up to redshift z~7 and refining our understanding of cosmic evolution since the universe’s infancy.
Using the James Webb Space Telescope, COSMOS-Web maps the universe’s cosmic web—the largest-scale structure—back to about 1 billion years after the Big Bang, delivering deeper, higher-resolution views than Hubble and enabling study of galaxy evolution in filaments and clusters across cosmic time.
Using the James Webb Space Telescope’s COSMOS-Web survey, researchers produced the sharpest map yet of the universe’s cosmic web by charting about 164,000 galaxies, tracing large-scale structures back to when the universe was roughly 1 billion years old. The map reveals dense filaments and voids and will help study how galaxies evolve within this cosmic skeleton; the data are publicly released for wider use.
Astronomers mapping the Milky Way’s dust-shrouded Zone of Avoidance have revealed the Vela Supercluster, a vast structure about 300 million light-years across containing roughly 33,800 trillion solar masses, located around 870 million light-years away. Using 65,518 galaxy distance measurements plus 8,283 new redshifts from SALT and MeerKAT, they show Vela is comparable in mass to the Shapley Supercluster and its gravity exceeds that of the Great Attractor, helping explain observed cosmic flows and completing our map of the local universe.
Researchers have mapped the Vela Supercluster, a massive galaxy assembly hidden behind the Milky Way’s dust in the Zone of Avoidance. Using SALT and the MeerKAT radio telescope, the structure—about 300 million light-years across and roughly 800 million light-years from Earth—contains the mass of ~30 quadrillion suns, making it one of the largest known local-universe structures. The discovery, ten years after its initial identification, helps refine models of cosmology and the distribution of matter in the universe, with future radio telescopes expected to yield even more detailed maps.
Scientists have developed Effort.jl, a fast and accurate emulator that mimics complex models of the universe's large-scale structure, enabling faster analysis of cosmic data from surveys like DESI and Euclid without sacrificing precision.
Astronomers using the MIGHTEE-HI survey discovered a 5.5 million light-year-long rotating galaxy filament connecting 14 galaxies, providing new insights into the early stages of cosmic web structures and galaxy evolution.
The cosmic neutrino background, a relic from the early stages of the hot Big Bang, has not been directly detected yet. However, evidence for its existence has been found indirectly through its imprints on the cosmic microwave background (CMB) and the clustering of galaxies in the large-scale structure of the Universe. Direct detection of the cosmic neutrino background is challenging due to the extremely tiny cross-section of neutrinos for interacting with other particles. Current experiments are not capable of detecting the signals from these relic neutrinos unless novel physics or technological advancements are involved. Future observations with more precise CMB measurements and large-scale structure surveys may provide further evidence for the cosmic neutrino background.
The growth of the large-scale structure of the universe, which is mostly composed of dark matter, is slower than expected, according to a recent analysis. This discrepancy, known as the S8 tension, suggests a suppression of growth beyond what is predicted by the standard model. The evidence for this suppression comes from multiple cosmological data sets and indicates a deviation from the standard model's picture. The late-time suppressed growth could have implications for our understanding of dark energy and gravity, and it may help alleviate the S8 tension. Further research is needed to determine whether this discrepancy is due to new physics or systematic errors in the measurements and analyses.