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Suppression without Thawing: Constraining Structure Formation and Dark Energy with Galaxy Clustering
Shi-Fan Chen1, Mikhail M Ivanov2, Oliver H E Philcox3,4
1School of Natural Sciences, <a href="https://ror.org/00f809463">Institute for Advanced Study</a>, 1 Einstein Drive, Princeton, New Jersey 08540, USA.
Physical Review Letters
|December 23, 2024
Summary
This study analyzes BOSS galaxy clustering data, finding suppressed cosmic structure at low redshifts. The results challenge the standard cosmological model and suggest potential data systematics or the need for new theoretical frameworks.
Area of Science:
- Cosmology
- Astrophysics
- Galaxy Evolution
Background:
- The Lambda Cold Dark Matter (ΛCDM) model is the standard cosmological model.
- Previous studies have indicated potential tensions between cosmic microwave background (CMB) data and low-redshift observations.
Purpose of the Study:
- To perform a comprehensive analysis of Baryon Oscillation Spectroscopic Survey (BOSS) galaxy clustering data.
- To constrain cosmological parameters and investigate the nature of dark energy.
- To assess the concordance between BOSS data and other cosmological datasets.
Main Methods:
- Perturbative full-shape analysis of BOSS galaxy power spectrum and bispectrum multipoles.
- Incorporation of baryon acoustic oscillations (BAO) and cross-correlations with Planck CMB gravitational lensing.
- Constraining cosmological parameters within the ΛCDM framework.
Main Results:
- Constrained matter density fraction Ωm=0.3138±0.0086, Hubble constant H0=68.23±0.78 km/s/Mpc, and σ8=0.688±0.026 (S8=0.703±0.029).
- Observed a significant (4.5σ) suppression of cosmic structure at low redshifts compared to the Planck ΛCDM model.
- Found no preference for dynamical dark energy (DDE) when combining BOSS data with DESI BAO and PantheonPlus supernovae, with dark energy consistent with a cosmological constant.
Conclusions:
- The observed suppression of cosmic structure may indicate residual systematics in the data or the need for new theoretical models.
- Cosmological concordance remains a challenge, requiring further investigation into potential discrepancies between different datasets and theoretical predictions.
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