Growth of structure in interacting vacuum cosmologies

Abstract

We examine the growth of structure in three different cosmological models with interacting dark matter and vacuum energy. We consider the case of geodesic dark matter with zero sound speed, where the relativistic growing mode in comoving-synchronous gauge coincides with the Newtonian growing mode at first order in $\Lambda$CDM. We study corrections to the linearly growing mode in the presence of interactions and the linear matter growth rate, $f_1$, contrasting this with the velocity divergence, $f_{rsd}{\sigma }_8$, observed through redshift-space distortions. We then derive second-order density perturbations in these interacting models. We identify the reduced bispectrum that corresponds to the non-linear growth of structure and show how the shape of the bispectrum is altered by energy transfer to or from the vacuum. Thus the bispectrum, or higher-order correlators, might in future be used to identify dark matter interactions.

19 pages, 5 figures; v2 references added; v3 matter density parameter in model (ii) corrected, figures and discussion revised, version accepted for publication in PRD

References in corpus (12)

• Dynamics of dark energy
• Large-scale instability in interacting dark energy and dark matter fluids
• Indications of a late-time interaction in the dark sector
• Effects of the interaction between dark energy and dark matter on cosmological parameters
• Dynamical vacuum energy in the expanding Universe confronted with observations: a dedicated study
• Possible signals of vacuum dynamics in the Universe
• Constraints on the interacting vacuum -- geodesic CDM scenario
• Cosmological constraints on a decomposed Chaplygin gas
• Inhomogeneous vacuum energy
• Einstein's signature in cosmological large-scale structure
• Constraining modified theory of gravity with galaxy bispectrum
• Number Counts and Dynamical Vacuum Cosmologies

Cited by in corpus (16)

• Constraints on the interacting vacuum -- geodesic CDM scenario
• Looking for interactions in the cosmological dark sector
• J-PAS: forecasts on interacting dark energy from baryon acoustic oscillations and redshift-space distortions
• J-PAS: forecasts on interacting vacuum energy models
• Nonsingular Cosmology from an Interacting Vacuum
• Differentiating dark interactions with perturbation
• Observational constraints on interacting vacuum energy with linear interactions
• Unphysical properties in a class of interacting dark energy models
• Testing the growth rate in homogeneous and inhomogeneous interacting vacuum models
• The interacting vacuum and tensions: a comparison of theoretical models
• Perturbations in the interacting vacuum
• Qualitative dynamics of interacting vacuum cosmologies
• Interacting dark matter and cosmic acceleration
• Difficulties in reconciling non-negligible differences between the local and cosmological values of the gravitational coupling in extended Brans-Dicke theories
• Galaxy number counts at second order in perturbation theory: a leading-order term comparison
• Perturbations In Some Dark Energy Models