Structure formation in the presence of dark energy perturbations

Abramo, L. Raul; Batista, R.C.; Liberato, Luana; Rosenfeld, R.

doi:10.1088/1475-7516/2007/11/012

Cited by 154 publications

(191 citation statements)

References 43 publications

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“…Another approach to calculate the extrapolated linear density contrast δ c as a function of collapse redshift has been discussed in [27]. Both approaches are found to be in agreement with each other.…”

Section: A Non-linear and Linear Matter Evolutionmentioning

confidence: 65%

Constraining thawing and freezing models with cluster number counts

Devi¹,

González²,

Alcaniz³

2014

J. Cosmol. Astropart. Phys.

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Measurements of the cluster abundance as a function of mass and redshift provide an important cosmological test that probe not only the expansion rate but also the growth of perturbations. In this paper we adopt a scalar field scenario which admits both thawing and freezing solutions from an appropriate choice of the model parameters and derived all relevant expressions to calculate the mass function and the cluster number density. We discuss the ability of cluster observations to distinguish between these scalar field behaviors and the standard ΛCDM scenario by considering the eROSITA and SPT cluster surveys.PACS numbers: 98.80.Es, 95.36.+x

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Section: A Non-linear and Linear Matter Evolutionmentioning

confidence: 65%

Constraining thawing and freezing models with cluster number counts

Devi¹,

González²,

Alcaniz³

2014

J. Cosmol. Astropart. Phys.

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“…We first start with quantities derived in the framework of the spherical collapse model and we continue with a discussion of how rotation and shear affect the mass function in clustering dark energy cosmologies. As shown in Batista & Pace (2013), the main difficulty is to study the evolution of dark energy perturbations in the non-linear regime (see also Mota & van de Bruck 2004;Nunes & Mota 2006;Abramo et al 2007;Creminelli et al 2010;Basse et al 2011). Batista & Pace (2013) clearly demonstrated that dark energy fluctuations are very sensitive to the value of c 2 eff : when c 2 eff = 1, on small scales, where non-linear evolution is important, dark energy fluctuations are negligible with respect to the dark matter fluctuations δDM therefore ignoring them when solving the system of equations describing the ESCM (Equations 11, 12, 14 and 24) does not introduce any significant error.…”

Section: Resultsmentioning

confidence: 99%

Effects of shear and rotation on the spherical collapse model for clustering dark energy

Pace¹,

Batista²,

Popolo³

2014

Monthly Notices of the Royal Astronomical Society

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In the framework of the spherical collapse model we study the influence of shear and rotation terms for dark matter fluid in clustering dark energy models. We evaluate, for different equations of state, the effects of these terms on the linear overdensity threshold parameter, δ c , and on the virial overdensity, ∆ V . The evaluation of their effects on δ c allows us to infer the modifications occurring on the mass function. Due to ambiguities in the definition of the halo mass in the case of clustering dark energy, we consider two different situations: the first is the classical one where the mass is of the dark matter halo only, while the second one is given by the sum of the mass of dark matter and dark energy. As previously found, the spherical collapse model becomes mass dependant and the two additional terms oppose to the collapse of the perturbations, especially on galactic scales, with respect to the spherical non-rotating model, while on clusters scales the effects of shear and rotation become negligible. The values for δ c and ∆ V are higher than the standard spherical model. Regarding the effects of the additional non-linear terms on the mass function, we evaluate the number density of halos. As expected, major differences appear at high masses and redshifts. In particular, quintessence (phantom) models predict more (less) objects with respect to the ΛCDM model and the mass correction due to the contribution of the dark energy component has negligible effects on the overall number of structures.

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“…In the work of Abramo et al (2007) the equation for the evolution of δ was generalized to a universe containing a DE component with a time-dependent EoS. The differential equation for the evolution of the overdensity δ in DE cosmologies and in the presence of rotation and shear tensors has been derived in del Popolo et al (2013a,b).…”

Section: Spherical Collapse In Hde Modelsmentioning

confidence: 99%

Evolution of spherical overdensities in holographic dark energy models

Naderi¹,

Malekjani²,

Pace³

2015

Monthly Notices of the Royal Astronomical Society

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In this work we investigate the spherical collapse model in flat FRW dark energy universes. We consider the Holographic Dark Energy (HDE) model as a dynamical dark energy scenario with a slowly time-varying equation-of-state (EoS) parameter w de in order to evaluate the effects of the dark energy component on structure formation in the universe. We first calculate the evolution of density perturbations in the linear regime for both phantom and quintessence behavior of the HDE model and compare the results with standard Einstein-de Sitter (EdS) and ΛCDM models. We then calculate the evolution of two characterizing parameters in the spherical collapse model, i.e., the linear density threshold δ c and the virial overdensity parameter ∆ vir . We show that in HDE cosmologies the growth factor g(a) and the linear overdensity parameter δ c fall behind the values for a ΛCDM universe while the virial overdensity ∆ vir is larger in HDE models than in the ΛCDM model. We also show that the ratio between the radius of the spherical perturbations at the virialization and turn-around time is smaller in HDE cosmologies than that predicted in a ΛCDM universe. Hence the growth of structures starts earlier in HDE models than in ΛCDM cosmologies and more concentrated objects can form in this case. It has been shown that the non-vanishing surface pressure leads to smaller virial radius and larger virial overdensity ∆ vir . We compare the predicted number of halos in HDE cosmologies and find out that in general this value is smaller than for ΛCDM models at higher redshifts and we compare different mass function prescriptions. Finally, we compare the results of the HDE models with observations.

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Structure formation in the presence of dark energy perturbations

Cited by 154 publications

References 43 publications

Constraining thawing and freezing models with cluster number counts

Constraining thawing and freezing models with cluster number counts

Effects of shear and rotation on the spherical collapse model for clustering dark energy

Evolution of spherical overdensities in holographic dark energy models

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