Published Article: The emperor’s new arc: gigaparsec patterns abound in a ΛCDM universe
In this article, we study the recent discoveries of large-scale features in the structure of the Universe that extend over hundreds of megaparsecs in apparent conflict with the standard model of cosmology. Using the very large FLAMINGO-10K simulation we show that such patterns are, in fact, commong and expected in a ΛCDM universe.
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 – ΛCDM) 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 ΛCDM 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 ΛCDM universe. We also show that their reported significant overdensities are an algorithmic artefact and unlikely to reflect any underlying structure.