Reconstruction of the null-test for the matter density perturbations

Abstract

We systematically study the null-test for the growth rate data first presented in [S. Nesseris and D. Sapone, arXiv:1409.3697.] and we reconstruct it using various combinations of data sets, such as the fσ 8 and HðzÞ or type Ia supernovae data. We perform the reconstruction in two different ways, either by directly binning thedata or by fitting various dark energy models. We also examine how well the null-test can be reconstructed by future data by creating mock catalogs based on the cosmological constant model, a model with strong dark energy perturbations, the fðRÞ and fðGÞ models, and the large void LemaitreTolman-Bondi model that exhibit different evolution of the matter perturbations. We find that with future data similar to an LSST-like survey, the null-test will be able to successfully discriminate between these different cases at the 5σ level.

Testing Einstein’s gravity and dark energy with growth of matter perturbations: Indications for new physics?

“…The mocks were created following the methodology of Ref. [13] having in mind a setup similar to Euclid-like and LSST-like surveys. To actually create the data, we evaluated the f σ 8 (z) for the ΛCDM cosmology, uniformly distributed in the range z ∈ [0, 2] divided into 10 equally spaced bins of step dz = 0.2.…”

“…545 ± 0.122 −0.558 ± 0.532 0.687 ± 0.095 6.999 13.856 wCDM 0.550 ± 0.122 −0.576 ± 0.532 0.687 ± 0.097 6.998 13.855 CPL 0.552 ± 0.122 −0.558 ± 0.533 0.689 ± 0.099 6.995 13.852 HDE 0.553 ± 0.122 −0.382 ± 0.543 0.699 ± 0.104 6.992 13.849 ΛtCDM 0.549 ± 0.123 −0.559 ± 0.537 0.687 ± 0.095 6.999 13.856 DGP 0.670 ± 0.143 −0.992 ± 0.555 0.687 ± 0.154 6.98513.842FRDE f (T ) 0.551 ± 0.122 −0.573 ± 0.532 0.688 ± 0.098 6.998 13.855 f (R) 0.555 ± 0.123 −0.580 ± 0.535 0.688 ± 0.098 6.997 13.854 For the CPL model:χ 2 gr,min = 13.445 (AIC=17.712), γ 0 = 0.564 ± 0.176 and γ 1 = −0.430 ± 1.454. • For the HDE model:χ 2 gr,min = 13.412 (AIC=17.679), γ 0 = 0.565 ± 0.177 and γ 1 = −0.235 ± 1.592.…”

Null tests of the standard model using the linear model formalism

“…While the previous tests probe the background structure of the universe, the test proposed in [15] (and deeply investigated in [29]) is sensitive to both background and perturbation observables. The ns diagnostic is able to test the validity of the growth of matter perturbations under the assumption of an FLRW metric with a cosmological constant (which has no perturbations).…”

Growth index of matter perturbations in running vacuum models

“…Clearly, in the case of the usual Λ cosmology (ν = 0, Ψ 0 = 0) the above formula boils down to that of Polarski & Gannouji [46] for y(z) = z (Γ 2 parametrization). Furthermore, based on the ΛCDM cosmological model and for y(z) = 1 − a(z) = z 1+z (Γ 1 parametrization), we also The growth data can be found in [50] (see their Table 1). For the ΛCDM we use σ8 = 0.829 while for the running vacuum model we have σ8 = 0.758 (see [23,25]).…”