The emperor’s new arc: gigaparsec patterns abound in a ΛCDM universe
Year: 2025
Type: article
Abstract: ABSTRACT Recent discoveries of apparent large-scale features in the structure of the Universe extending over many hundreds of megaparsecs, have been claimed to contradict the large-scale isotropy and homogeneity foundational to the standard (Lambda cold dark matter – $\Lambda$CDM) cosmological model. We explicitly test and refute this conjecture using FLAMINGO-10K, a new and very large cosmological simulation of the growth of structure in a $\Lambda$CDM context. Applying the same methods used in the observations, we show that patterns like the ‘Giant Arc’, supposedly in tension with the standard model, are, in fact, common and expected in a $\Lambda$CDM universe. We also show that their reported significant overdensities are an algorithmic artefact and unlikely to reflect any underlying structure.
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $1,451
Awards: Durham DiRAC-2 petascale facility, DiRAC-2.5 - the pathway to DiRAC Phase 3, Post-Newtonian modelling of the dynamics of supermassive black holes in galactic-scale hydrodynamical simulations (KETJU), APRIORI - AstroPhysical ReconstructIons with OctRee Inference, The role of supermassive black holes in the cosmological formation of massive galaxies, DiRAC-2.5 DC - Operations 2017-2020, DiRAC: Memory Intensive 2.5y, Astrophysical constraints on the identity of the dark matter, DiRAC: Memory Intensive 2.5x
OpenAlex ID: W4408317726