Constraints from growth-rate data on some coupled dark energy models mimicking a $\Lambda CDM$ expansion

Abstract

The $\Lambda CDM$ expansion could be mimicked by a dark energy coupled to matter. Then, the equation of state $\bar{w}$ and coupling $\bar{Q}$ of this coupled dark energy could not be constrained by observations of the Hubble function alone. Also, in this paper, we determine the constraints on two such coupled dark energy models considering some current and forecast Euclid-like growth-rate data and assuming the prior on the $\Lambda CDM$ dark matter density parameter today ${\Omega }_{m0}=0.295\pm 0.04$. The first model is defined by a constant equation of state. We find that at $2\sigma$, $\bar{w}=-1.02_{-0.22}^{+0.06}$ and the coupling function ${\bar{Q}}_0$ today is ${\bar{Q}}_0{H}_0^{-3}=0.057_{-0.148}^{+0.353}$ with $H_0$ the Hubble constant. The second model is defined by a varying equation of state $\bar{w}={\bar{w}}_a-{\bar{w}}_b\ln (1+z)$, with $z$ the redshift and $({\bar{w}}_a,{\bar{w}}_b)$, two constants. We find that at $2\sigma$, ${\bar{w}}_a=-0.99_{-0.90}^{+0.17}$, ${\bar{w}}_b=-0.04_{-1.17}^{+0.31}$ and ${\bar{Q}}_0{H}_0^{-3}=0.0002_{-0.18}^{+1.35}$. These constraints on coupled dark energy agreed with a $\Lambda CDM$ model but are too poor to discard confidently a coupled dark energy different from vacuum but mimicking a $\Lambda CDM$ expansion.

7 pages, 5 figures, accepted for publication in MNRAS

References in corpus (9)

• Baryon Acoustic Oscillations in the Lyα forest of BOSS DR11 quasars
• Breaking a Dark Degeneracy with Gravitational Waves
• Can f(R) Modified Gravity Theories Mimic a LCDM Cosmology?
• How to Distinguish Dark Energy and Modified Gravity?
• Evolution of density perturbations in decaying vacuum cosmology
• Redshift drift exploration for interacting dark energy
• A cosmological exclusion plot: Towards model-independent constraints on modified gravity from current and future growth rate data
• Number Counts and Dynamical Vacuum Cosmologies
• Determining accurate measurements of the growth rate from the galaxy correlation function in simulations

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