Reconstructing the growth index $\gamma$ with Gaussian Processes

Abstract

Alternative cosmological models have been proposed to alleviate the tensions reported in the concordance cosmological model, or to explain the current accelerated phase of the universe. One way to distinguish between General Relativity and modified gravity models is using current astronomical data to measure the growth index $\gamma$, a parameter related to the growth of matter perturbations, which behaves differently in different metric theories. We propose a model independent methodology for determining $\gamma$, where our analyses combine diverse cosmological data sets, namely $\{f(z_i)\}$, $\{[f{\sigma }_8](z_i)\}$, and $\{H(z_i)\}$, and use Gaussian Processes, a non-parametric approach suitable to reconstruct functions. This methodology is a new consistency test for $\gamma$ constant. Our results show that, for the redshift interval $0<z<1$, $\gamma$ is consistent with the constant value $\gamma =0.55$, expected in General Relativity theory, within $2\sigma$ confidence level (CL). Moreover, we find $\gamma (z=0)$ = 0.311 $\pm 0.144$ and $\gamma (z=0)=0.609\pm 0.200$ for the reconstructions using the $\{f(z_i)\}$ and $\{[f{\sigma }_8](z_i)\}$ data sets, respectively, values that also agree at a 2$\sigma$ CL with $\gamma =0.55$. Our methodology and analyses can be considered as an alternative approach in light of the current discussion in the literature that suggests a possible evidence for the growth index evolution.

arXiv comment11 pages and 8 figures

References in corpus (71)

• Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
• Measurements of Omega and Lambda from 42 High-Redshift Supernovae
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• In the Realm of the Hubble tension $-$ a Review of Solutions
• Dark Energy and the Accelerating Universe
• Observational Probes of Cosmic Acceleration
• Cosmic Chronometers: Constraining the Equation of State of Dark Energy. I: H(z) Measurements
• Cosmology and Fundamental Physics with the Euclid Satellite
• Constraining Cosmological Parameters Based on Relative Galaxy Ages
• Cluster Abundance Constraints on Quintessence Models
• Challenges for $\Lambda$CDM: An update
• Cosmic Growth History and Expansion History
• Cosmology Intertwined III: $f{\sigma }_8$ and $S_8$
• Reconstruction of dark energy and expansion dynamics using Gaussian processes
• Gaussian Process Cosmography
• Setting the Stage for Cosmic Chronometers. II. Impact of Stellar Population Synthesis Models Systematics and Full Covariance Matrix
• $H_0$ from cosmic chronometers and Type Ia supernovae, with Gaussian Processes and the novel Weighted Polynomial Regression method
• Nonparametric Dark Energy Reconstruction from Supernova Data
• The WiggleZ Dark Energy Survey: the transition to large-scale cosmic homogeneity
• Hubble expansion & Structure Formation in Time Varying Vacuum Models
• Viable f(T) models are practically indistinguishable from LCDM
• Arbitrating the $S_8$ discrepancy with growth rate measurements from Redshift-Space Distortions
• On the growth of linear perturbations
• Nonparametric Reconstruction of the Dark Energy Equation of State
• Two Windows on Acceleration and Gravitation: Dark Energy or New Gravity?
• Reconstructing the interaction between dark energy and dark matter using Gaussian Processes
• Setting the Stage for Cosmic Chronometers. I. Assessing the Impact of Young Stellar Populations on Hubble Parameter Measurements
• Nonparametric Reconstruction of the Dark Energy Equation of State from Diverse Data Sets
• Anomalies in Physical Cosmology
• Evidence for suppression of structure growth in the concordance cosmological model
• Gaussian Process Estimation of Transition Redshift
• Model-independent reconstruction of the Interacting Dark Energy Kernel: Binned and Gaussian process
• Tension of the $E_G$ statistic and RSD data with Planck/$\Lambda$CDM and implications for weakening gravity
• Growth Index of DGP Model and Current Growth Rate Data
• Exploring cosmic homogeneity with the BOSS DR12 galaxy sample
• How to use GP: Effects of the mean function and hyperparameter selection on Gaussian Process regression
• Measurements of $H_0$ and reconstruction of the dark energy properties from a model-independent joint analysis
• Cosmology with the Large Synoptic Survey Telescope: an Overview
• Falsifying $\Lambda$CDM: Model-independent tests of the concordance model with eBOSS DR14Q and Pantheon
• Skewness as a test of the equivalence principle
• Gaussian processes reconstruction of dark energy from observational data
• Inferring $S_8(z)$ and $\gamma (z)$ with cosmic growth rate measurements using machine learning
• Assessment of the cosmic distance duality relation using Gaussian Process
• $S_8$ increases with effective redshift in $\Lambda$CDM cosmology
• Constraints on growth index parameters from current and future observations
• Model-independent cosmological constraints from growth and expansion
• Model-independent constraints on ${\Omega }_m$ and $H(z)$ from the link between geometry and growth
• Tomographic analyses of the CMB lensing and galaxy clustering to probe the linear structure growth
• Baryon acoustic oscillations signature in the three-point angular correlation function from the SDSS-DR12 quasar survey
• Influence of the Bounds of the Hyperparameters on the Reconstruction of Hubble Constant with Gaussian Process
• The scale of homogeneity in the local Universe with the ALFALFA catalogue
• Model independent bounds on Type Ia supernova absolute peak magnitude
• The angular scale of homogeneity in the Local Universe with the SDSS blue galaxies
• Non-parametric reconstruction of cosmological matter perturbations
• The homogeneity scale and the growth rate of cosmic structures
• Defying the laws of Gravity I: model-independent reconstruction of the Universe expansion from growth data
• Isotropy analyses of the Planck convergence map
• When is the growth index constant?
• C${}^3$-Cluster Clustering Cosmology I. New constraints on the cosmic growth rate at z~0.3 from redshift-space clustering anisotropies
• The $\Lambda$CDM growth rate of structure revisited
• Kernel Selection for Gaussian Process in Cosmology: with Approximate Bayesian Computation Rejection and Nested Sampling
• Precision growth index using the clustering of cosmic structures and growth data
• On the use of galaxies as clocks and the universal expansion
• Imprints of interacting dark energy on cosmological perturbations
• Non-parametric Reconstruction of Growth Index via Gaussian Processes
• Joint reconstructions of growth and expansion histories from stage-IV surveys with minimal assumptions. II. Modified gravity and massive neutrinos
• Sweeping Horndeski Canvas: New Growth-Rate Parameterization for Modified-Gravity Theories
• Probing cosmic isotropy in the Local Universe
• Model-independent estimation of the cosmography parameters using cosmic chronometers
• Analytical Gaussian Process Cosmography: Unveiling Insights into Matter-Energy Density Parameter at Present
• A new consistency test for $\Lambda$CDM cosmology using galaxy surveys

Cited by in corpus (11)

• The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics
• Consistency tests between SDSS and DESI BAO measurements
• Linear matter density perturbations in the ${\Lambda }_{\mathrm{s}}$CDM model: Examining growth dynamics and addressing the $S_8$ tension
• Measuring the matter fluctuations in the Local Universe with the ALFALFA catalog
• A comprehensive data-driven odyssey to explore the equation of state of dark energy
• Is ${\omega }_0{\omega }_a$CDM a good model for the clumpy Universe?
• Viability of general relativity and modified gravity cosmologies using high-redshift cosmic probes
• Probing the Cosmic Distance Duality Relation via Non-Parametric Reconstruction for High Redshifts
• Revisiting the temperature evolution law of the CMB with gaussian processes
• Scalar perturbation and density contrast evolution in $f(Q,C)$ gravity
• Testing Scale-Dependent Suppression of Structure Growth in the Linear Regime