The growth of density perturbations in the last $\sim$10 billion years from tomographic large-scale structure data

Abstract

In order to investigate the origin of the ongoing tension between the amplitude of matter fluctuations measured by weak lensing experiments at low redshifts and the value inferred from the cosmic microwave background anisotropies, we reconstruct the evolution of this amplitude from z ∼ 2 using existing large-scale structure data. To do so, we decouple the linear growth of density inhomogeneities from the background expansion, and constrain its redshift dependence making use of a combination of 6 different data sets, including cosmic shear, galaxy clustering and CMB lensing. We analyze these data under a consistent harmonic-space angular power spectrum-based pipeline. We show that current data constrain the amplitude of fluctuations mostly in the range 0.2 < z < 0.7, where it is lower than predicted by Planck. This difference is mostly driven by current cosmic shear data, although the growth histories reconstructed from different data combinations are consistent with each other, and we find no evidence of systematic deviations in any particular experiment. In spite of the tension with Planck, the data are well-described by the ΛCDM model, albeit with a lower value of S 8 ≡ σ 8 (Ω m /0.3) 0.5 . As part of our analysis, we find constraints on this parameter of S 8 = 0.7769 ± 0.0095 (68% confidence level), reaching almost percent-level errors comparable with CMB measurements.

Model-independent constraints on $Ω_m$ and $H(z)$ from the link between geometry and growth

“…This is consistent with the underprediction of 𝑓𝜎 8 between 0 < 𝑧 < 0.75 we discussed in the previous section. A lower value of 𝑆 8 would also be consistent with the most recent measurements by large scale structure experiments (Heymans et al 2021;DES Collaboration et al 2021b;García-García et al 2021;White et al 2021;Krolewski et al 2021), the origin of which could lie on a lower value of Ω 𝑚 (Hang et al 2021).…”

“…This result is lower than, but statically compatible with, the Planck 2018 (Planck Collaboration et al 2020) cosmology. We also find 𝑆 8 = 0.788 ± 0.029, an intermediate value, statistically compatible with both the Planck 2018 cosmology (Planck Collaboration et al 2020) and recent local measurements from weak lensing and galaxy clustering(DES Collaboration et al 2021b;Heymans et al 2021;García-García et al 2021;Krolewski et al 2021;White et al 2021). …”

“…The development of tools such as differentiable Boltzmann codes, differentiable emulators of the non-linear matter power spectrum, or differentiable Limber integrators would allow us to fit the power spectrum data directly. These developments would enable modelagnostic analyses similar to that of García-García et al (2021) but with a greatly reduced number of assumptions and a more reliable measure of uncertainty in their results. On the other hand, it would also be possible to explore the use of Gaussian processes to constrain general forms of modified gravity, generalizing works such as Raveri et al (2017); Espejo et al (2019); Park et al (2021); Raveri et al (2021); Pogosian et al (2021), and study how these theories can be informed by the relationship between background and perturbations.…”

“…Riess et al 2021;Freedman et al 2020;Pesce et al 2020) or the density-weighted amplitude of fluctuations, 𝑆 8 ≡ 𝜎 8 (Ω 𝑚 /0.3) 0.5 (e.g. Asgari et al 2021;DES Collaboration et al 2021a;Alsing et al 2017;Nunes & Vagnozzi 2021;Heymans et al 2021;Ruiz-Zapatero et al 2021;García-García et al 2021;White et al 2021), where 𝜎 8 is the variance of 𝛿, in spheres of radius 8 ℎ −1 Mpc.…”

Cosmological constraints from the tomographic cross-correlation of DESI Luminous Red Galaxies and Planck CMB lensing

“…In a recent analysis of a wide range of data sets, ref. [32] find evidence for a deficit in the growth of large scale structure in the redshift regime 0.2 < z < 0.6.…”