{ "id": "2302.01331", "version": "v1", "published": "2023-02-02T18:59:19.000Z", "updated": "2023-02-02T18:59:19.000Z", "title": "Evidence for suppression of structure growth in the concordance cosmological model", "authors": [ "Nhat-Minh Nguyen", "Dragan Huterer", "Yuewei Wen" ], "comment": "5 pages + references; 5 figures, 2 tables, 2900 words. Comments welcome!", "categories": [ "astro-ph.CO", "gr-qc" ], "abstract": "We present evidence for a suppressed growth rate of large-scale structure during the dark-energy dominated era. Modeling the growth rate of perturbations with the ``growth index'' $\\gamma$, we find that current cosmological data strongly prefer a higher growth index than the value $\\gamma=0.55$ predicted by general relativity in a flat $\\Lambda$CDM cosmology. Both the cosmic microwave background data from Planck and the large-scale structure data from weak lensing, galaxy clustering, and cosmic velocities separately favor growth suppression. When combined, they yield $\\gamma=0.633^{+0.025}_{-0.024}$, excluding $\\gamma=0.55$ at a statistical significance of 3.7$\\sigma$. The combination of $f\\sigma_8$ and Planck measurements prefers an even higher growth index of $\\gamma=0.639^{+0.024}_{-0.025}$, corresponding to a 4.2$\\sigma$-tension with the concordance model. In Planck data, the suppressed growth rate offsets the preference for nonzero curvature and fits the data equally well as the latter model. A higher $\\gamma$ leads to a higher matter fluctuation amplitude $S_8$ inferred from galaxy clustering and weak lensing measurements, and a lower $S_8$ from Planck data, effectively resolving the $S_8$ tension.", "revisions": [ { "version": "v1", "updated": "2023-02-02T18:59:19.000Z" } ], "analyses": { "keywords": [ "concordance cosmological model", "structure growth", "separately favor growth suppression", "velocities separately favor growth", "higher growth index" ], "note": { "typesetting": "TeX", "pages": 5, "language": "en", "license": "arXiv", "status": "editable" } } }