Geometry versus growth

Ruiz-Zapatero, Jaime; Stölzner, Benjamin; Joachimi, Benjamin; Asgari, Marika; Bilicki, Maciej; Dvornik, Andrej; Giblin, Benjamin; Heymans, Catherine; Hildebrandt, Hendrik; Kannawadi, Arun; Kuijken, K.; Tröster, Tilman; Busch, Jan Luca van den; Wright, Angus H.

doi:10.1051/0004-6361/202141350

“…In [272], it is shown how two independent sets of cosmological parameters, the background (geometrical) and the matter density (growth) component parameters, respectively, give consistent results and how the preference for high values of H 0 is less significant in their analysis.…”

Section: Introductionmentioning

confidence: 99%

On the Evolution of the Hubble Constant with the SNe Ia Pantheon Sample and Baryon Acoustic Oscillations: A Feasibility Study for GRB-Cosmology in 2030

Dainotti

¹

,

Simone

²

,

Schiavone

³

et al. 2022

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The difference from 4 to 6 σ in the Hubble constant (H0) between the values observed with the local (Cepheids and Supernovae Ia, SNe Ia) and the high-z probes (Cosmic Microwave Background obtained by the Planck data) still challenges the astrophysics and cosmology community. Previous analysis has shown that there is an evolution in the Hubble constant that scales as f(z)=H0/(1+z)η, where H0 is H0(z=0) and η is the evolutionary parameter. Here, we investigate if this evolution still holds by using the SNe Ia gathered in the Pantheon sample and the Baryon Acoustic Oscillations. We assume H0=70kms−1Mpc−1 as the local value and divide the Pantheon into three bins ordered in increasing values of redshift. Similar to our previous analysis but varying two cosmological parameters contemporaneously (H0, Ω0m in the ΛCDM model and H0, wa in the w0waCDM model), for each bin we implement a Markov-Chain Monte Carlo analysis (MCMC) obtaining the value of H0 assuming Gaussian priors to restrict the parameters spaces to values we expect from our prior knowledge of the current cosmological models and to avoid phantom Dark Energy models with w<−1. Subsequently, the values of H0 are fitted with the model f(z). Our results show that a decreasing trend with η∼10−2 is still visible in this sample. The η coefficient reaches zero in 2.0 σ for the ΛCDM model up to 5.8 σ for w0waCDM model. This trend, if not due to statistical fluctuations, could be explained through a hidden astrophysical bias, such as the effect of stretch evolution, or it requires new theoretical models, a possible proposition is the modified gravity theories, f(R). This analysis is meant to further cast light on the evolution of H0 and it does not specifically focus on constraining the other parameters. This work is also a preparatory to understand how the combined probes still show an evolution of the H0 by redshift and what is the current status of simulations on GRB cosmology to obtain the uncertainties on the Ω0m comparable with the ones achieved through SNe Ia.

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“…There is also a tension between the Planck S 8 = σ 8 Ω m /0.3 (where σ 8 is the RMS matter fluctuation averaged over a sphere of radius 8 h −1 Mpc and Ω m is the fractional matter density) constraint in ΛCDM and ground-based weak lensing shear measurements from surveys including DES and KiDS. The KiDS team report tensions with Planck at the (2.5 − 3.0)σ level depending on data cuts and analysis choices (Ruiz-Zapatero et al 2021;Asgari et al 2021). The recently completed DES 3-Year analysis concludes that the DES results overall are consistent with Planck , but S 8 from the shear measurements (separate from other probes such as galaxy clustering) is lower by (2.1 − 2.3)σ in the same direction as KiDS (Amon et al 2021).…”

Section: For a Review)mentioning

confidence: 96%

An exploration of an early gravity transition in light of cosmological tensions

Benevento¹,

Kable²,

Addison³

et al. 2022

Preprint

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We study a step-like transition in the value of the effective Planck mass (or effective gravitational constant) on cosmological scales prior to recombination. We employ CMB, BAO, and SNIa data and find they are sufficient to strongly constrain our implementation of the Effective Field Theory of Dark Energy and Modified Gravity, used to model the transition, to a limited parameter space. The data prefer a ∼ 5% shift in the value of the effective Planck mass (< 10% at 2σ) prior to recombination. This Transitional Planck Mass (TPM) model is free to undergo its transition at any point over multiple decades of scale factor prior to recombination, log 10 (a) = −5.32 +0.96 −0.72 (68% CL). This lowers the sound horizon at last scattering, which increases the Hubble constant to 71.09 ± 0.75 km s −1 Mpc −1 with a combination of local measurements as prior and to 69.22 +0.67 −0.86 km s −1 Mpc −1 when the prior is excluded. The TPM model improves χ 2 with respect to ΛCDM by ∆χ 2 = −23.72 with the H 0 prior and ∆χ 2 = −4.8 without the prior. The model allows for both H 0 > 70 kms −1 Mpc −1 and S 8 < 0.80 simultaneously with lower values of S 8 due to a reduction in the matter density Ω m to offset the increase in H 0 relative to ΛCDM. While this is a particular modified gravity model, studying other variants of modified gravity may be a productive path for potentially resolving cosmological tensions, while avoiding the need for a cosmological constant.

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“…There is also a tension between the Planck S 8 = 0.3 m 8 s W (where σ 8 is the rms matter fluctuation averaged over a sphere of radius 8 h −1 Mpc and Ω m is the fractional matter density) constraint in Λ CDM and ground-based weak lensing shear measurements from surveys including DES and KiDS. The KiDS team reported tensions with Planck at the (2.5-3.0)σ level depending on data cuts and analysis choices (Asgari et al 2021;Ruiz-Zapatero et al 2021). The recently completed DES 3 yr analysis concludes that the DES results overall are consistent with Planck, but S 8 from the shear measurements (separate from other probes such as galaxy clustering) is lower by (2.1-2.3)σ in the same direction as KiDS (Amon et al 2021).…”

Section: Introductionmentioning

confidence: 92%

An Exploration of an Early Gravity Transition in Light of Cosmological Tensions

Benevento

¹

,

Kable

²

,

Addison

³

et al. 2022

ApJ

View full text Add to dashboard Cite

We study a step-like transition in the value of the effective Planck mass (or effective gravitational constant) on cosmological scales prior to recombination. We employ cosmic microwave background, baryon acoustic oscillations, and Type Ia supernova data and find they are sufficient to strongly constrain our implementation of the effective field theory of dark energy and modified gravity, used to model the transition, to a limited parameter space. The data prefer a ∼5% shift in the value of the effective Planck mass (<10% at 2σ) prior to recombination. This Transitional Planck Mass (TPM) model is free to undergo its transition at any point over multiple decades of scale factor prior to recombination, log 10 ( a ) = − 5.32 − 0.72 + 0.96 (68% confidence level). This lowers the sound horizon at last scattering, which increases the Hubble constant to 71.09 ± 0.75 km s−1 Mpc−1 with a combination of local measurements as prior and to 69.22 − 0.86 + 0.67 km s−1 Mpc−1 when the prior is excluded. The TPM model improves χ 2 with respect to ΛCDM by Δχ 2 = −23.72 with the H 0 prior and Δχ 2 = −4.8 without the prior. The model allows for both H 0 > 70 kms−1 Mpc−1 and S 8 < 0.80 simultaneously with lower values of S 8 due to a reduction in the matter density Ω m to offset the increase in H 0 relative to ΛCDM. While this is a particular modified gravity model, studying other variants of modified gravity may be a productive path for potentially resolving cosmological tensions while avoiding the need for a cosmological constant.

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Geometry versus growth

Cited by 10 publications

References 100 publications

On the Evolution of the Hubble Constant with the SNe Ia Pantheon Sample and Baryon Acoustic Oscillations: A Feasibility Study for GRB-Cosmology in 2030

On the Evolution of the Hubble Constant with the SNe Ia Pantheon Sample and Baryon Acoustic Oscillations: A Feasibility Study for GRB-Cosmology in 2030

An exploration of an early gravity transition in light of cosmological tensions

An Exploration of an Early Gravity Transition in Light of Cosmological Tensions

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