Year: 2008
Type: article
Abstract: We have compiled a data set consisting of 22 data points at a redshift range (0.15, 3.8) which can be used to constrain the linear perturbation growth rate $f=\frac{d\mathrm{ln}\ensuremath{\delta}}{d\mathrm{ln}a}$. Five of these data points constrain directly the growth rate $f$ through either redshift distortions or change of the power spectrum with redshift. The rest of the data points constrain $f$ indirectly through the rms mass fluctuation ${\ensuremath{\sigma}}_{8}(z)$ inferred from ${L}_{y}\mathrm{\text{\ensuremath{-}}}\ensuremath{\alpha}$ at various redshifts. Our analysis tests the consistency of the $\ensuremath{\Lambda}\mathrm{CDM}$ model and leads to a constraint of the Wang-Steinhardt growth index $\ensuremath{\gamma}$ [defined from $f={\ensuremath{\Omega}}_{m}(a{)}^{\ensuremath{\gamma}}$] as $\ensuremath{\gamma}={0.67}_{\ensuremath{-}0.17}^{+0.20}$. This result is clearly consistent at $1\ensuremath{\sigma}$ with the value $\ensuremath{\gamma}=\frac{6}{11}=0.545$ predicted by $\ensuremath{\Lambda}\mathrm{CDM}$. We also apply our analysis on a new null test of $\ensuremath{\Lambda}\mathrm{CDM}$ which is similar to the one recently proposed by Chiba and Nakamura (arXiv:0708.3877) but does not involve derivatives of the expansion rate $H(z)$. This also leads to the fact that $\ensuremath{\Lambda}\mathrm{CDM}$ provides an excellent fit to the current linear growth data.
Authors: S. Nesseris, L. Perivolaropoulos
Institution: University of Ioannina
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funder: State Scholarships Foundation
OpenAlex ID: W2150124329