Model-independent constraints on Ωm and <i>H</i>(<i>z</i>) from the link between geometry and growth

Ruiz-Zapatero, Jaime; García-García, Carlos; Alonso, David; Ferreira, Pedro G.; Grumitt, R. D. P.

doi:10.1093/mnras/stac431

Cited by 23 publications

(8 citation statements)

References 79 publications

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“…This approach is based on the evolution equation for the growth rate f . (Note that [44] use the same equation but for a different purpose, i.e. to reconstruct the evolution of Ω m .…”

Section: Discussionmentioning

confidence: 99%

Measuring dark energy with expansion and growth

Pèrenon¹,

Martinelli²,

Maartens³

et al. 2022

Preprint

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We combine cosmic chronometer and growth of structure data to derive the redshift evolution of the dark energy equation of state w, using a novel agnostic approach. The background and perturbation equations lead to two expressions for w, one purely background-based and the other relying also on the growth rate of large-scale structure. We compare the features and performance of the growth-based w to the background w, using Gaussian Processes for the reconstructions. We find that current data is not precise enough for robust reconstruction of the two forms of w. By using mock data expected from next-generation surveys, we show that the reconstructions will be robust enough and that the growth-based w will out-perform the background w. Furthermore, any disagreement between the two forms of w will provide a new test for deviations from the standard model of cosmology.

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“…This approach is based on the evolution equation for the growth rate f . (Note that [44] use the same equation but for a different purpose, i.e. to reconstruct the evolution of Ω m .…”

Section: Discussionmentioning

confidence: 99%

Measuring dark energy with expansion and growth

Pèrenon¹,

Martinelli²,

Maartens³

et al. 2022

Preprint

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“…Ref. [25] used the ΛCDM best-fit with a multiplicative parameter as a mean function in order to give more flexibility than a constant mean function. While a constant mean function is legitimate in the case of stationary signals, in the case of a time-evolving quantity such as the distance moduli, or other cosmological quantities such as the Hubble expansion history, it is less clear.…”

Section: Role Of the Mean Functionmentioning

confidence: 99%

“…This idea is similar to the recent approach by ref. [25], who use the best-fit ΛCDM as a mean function and marginalize over a multiplicative parameter.…”

Section: Full-marginalizationmentioning

confidence: 99%

How to use GP: effects of the mean function and hyperparameter selection on Gaussian process regression

Hwang

L’Huillier

Keeley

et al. 2023

J. Cosmol. Astropart. Phys.

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Gaussian processes have been widely used in cosmology to reconstruct cosmological quantities in a model-independent way. However, the validity of the adopted mean function and hyperparameters, and the dependence of the results on the choice have not been well explored. In this paper, we study the effects of the underlying mean function and the hyperparameter selection on the reconstruction of the distance moduli from type Ia supernovae. We show that the choice of an arbitrary mean function affects the reconstruction: a zero mean function leads to unphysical distance moduli and the best-fit ΛCDM to biased reconstructions. We propose to marginalize over a family of mean functions and over the hyperparameters to effectively remove their impact on the reconstructions. We further explore the validity and consistency of the results considering different kernel functions and show that our method is unbiased.

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“…compile the 31 BAO data in Table 2, which are summarized in Refs. [66,102]. The dataset includes almost all the radial BAO data reported in various galaxy surveys.…”

Section: Bao Measurements Can Only Obtain the Combinationmentioning

confidence: 99%

Null test for cosmic curvature using Gaussian process*

Wu¹,

Qi²,

Zhang

2023

Chinese Phys. C

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The cosmic curvature ΩK,0, which determines the spatial geometry of the universe, is an important parameter in modern cosmology. Any deviation from ΩK,0=0 would have a profound impact on primordial inflation paradigm and fundamental physics. In this work, we adopt a cosmological model-independent method to test whether ΩK,0 deviates from zero. We use the Gaussian process to reconstruct the reduced Hubble parameter E(z) and the derivative of distance D′(z) from observational data, and then determine ΩK,0 with a null test relation. The cosmic chronometer (CC) Hubble data, baryon acoustic oscillation (BAO) Hubble data, and supernovae Pantheon sample are considered. Our result is consistent with a spatially flat universe within the domain of reconstruction 0<z<2.3, at the 1σ confidence level. In the redshift interval 0<z<1, the result favors a flat universe, while at z>1, it tends to favor a closed universe. In this sense, there is still a possibility for a closed universe. We also carry out the null test of the cosmic curvature at 0<z<4.5 using the simulated gravitational wave standard sirens, CC+BAO and redshift drift Hubble data. The result shows that in the future, with the synergy of multiple high-quality observations, we can tightly constrain the spatial geometry or exclude the flat universe.

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

Cited by 23 publications

References 79 publications

Measuring dark energy with expansion and growth

Measuring dark energy with expansion and growth

How to use GP: effects of the mean function and hyperparameter selection on Gaussian process regression

Null test for cosmic curvature using Gaussian process*

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