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arXiv · 2406.13388

Suppression without Thawing: Constraining Structure Formation and Dark Energy with Galaxy Clustering

Shi-Fan Chen·Mikhail M. Ivanov·Oliver H. E. Philcox·Lukas Wenzl
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Abstract

We present a new perturbative full-shape analysis of BOSS galaxy clustering data, including the full combination of the galaxy power spectrum and bispectrum multipoles, baryon acoustic oscillations, and cross-correlations with the gravitational lensing of cosmic microwave background measured from \textit{Planck}. Assuming the $\Lambda$CDM model, we constrain the matter density fraction $\Omega_m = 0.3138\pm 0.0086$, the Hubble constant $H_0=68.23\pm 0.78\,\mathrm{km}\,\mathrm{s}^{-1}\mathrm{Mpc}^{-1}$, and the mass fluctuation amplitude $\sigma_8=0.688\pm 0.026$ (equivalent to $S_8 = 0.703\pm 0.029$). Cosmic structure at low redshifts appears suppressed with respect to the Planck $\Lambda$CDM concordance model at $4.5\sigma$. We explore whether this tension can be explained by the recent DESI preference for dynamical dark energy (DDE): the BOSS data combine with DESI BAO and PantheonPlus supernovae competitively compared to the CMB, yielding no preference for DDE, but the same $\sim 10\%$ suppression of structure, with dark energy being consistent with a cosmological constant at 68\% CL. Our results suggest that either the data contains residual systematics, or more model-building efforts may be required to restore cosmological concordance.

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Shi-Fan Chen, Mikhail M. Ivanov, Oliver H. E. Philcox, Lukas Wenzl. 2024-06-19. Suppression without Thawing: Constraining Structure Formation and Dark Energy with Galaxy Clustering. https://arxiv.org/abs/2406.13388

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