Coupled dark energy: Parameter constraints from<i>N</i>-body simulations

Macciò, Andrea V.; Quercellini, Claudia; Mainini, Roberto; Amendola, Luca; Bonometto, S. A.

doi:10.1103/physrevd.69.123516

Cited by 164 publications

(255 citation statements)

References 29 publications

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“…[20,21,22,23,24]) have focused on modifications of the force law with a fixed and density independent range. Such modifications alone are incapable of satisfying local tests of gravity.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear evolution off(R)cosmologies. II. Power spectrum

2008

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We carry out a suite of cosmological simulations of modified action f (R) models where cosmic acceleration arises from an alteration of gravity instead of dark energy. These models introduce an extra scalar degree of freedom which enhances the force of gravity below the inverse mass or Compton scale of the scalar. The simulations exhibit the so-called chameleon mechanism, necessary for satisfying local constraints on gravity, where this scale depends on environment, in particular the depth of the local gravitational potential. We find that the chameleon mechanism can substantially suppress the enhancement of power spectrum in the non-linear regime if the background field value is comparable to or smaller than the depth of the gravitational potentials of typical structures. Nonetheless power spectrum enhancements at intermediate scales remain at a measurable level for models even when the expansion history is indistinguishable from a cosmological constant, cold dark matter model. Simple scaling relations that take the linear power spectrum into a non-linear spectrum fail to capture the modifications of f (R) due to the change in collapsed structures, the chameleon mechanism, and the time evolution of the modifications.

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“…[20,21,22,23,24]) have focused on modifications of the force law with a fixed and density independent range. Such modifications alone are incapable of satisfying local tests of gravity.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear evolution off(R)cosmologies. II. Power spectrum

2008

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“…In previous work this was considered a small strength. CMB data set a limit β <∼ 0.6; a stronger constraint found by [6], by studying cluster profiles in n-body simulations, applies to RP potentials only.…”

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confidence: 99%

“…In a number of papers, constraints on coupling, coming from CMB and LSS observations, were discussed [4,5,6]. This note aims at formulating predictions on the mass function of bound systems in coupled DE (cDE) cosmologies, by using Sheth & Tormen [9] expressions, known to improve the original Press & Schechter [8] approach.…”

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confidence: 99%

Mass functions in coupled dark energy models

Mainini

Bonometto

2006

Phys. Rev. D

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We evaluate the mass function of virialized halos, by using Press & Schechter (PS) and/or Steth & Tormen (ST) expressions, for cosmologies where Dark Energy (DE) is due to a scalar selfinteracting field, coupled with Dark Matter (DM). We keep to coupled DE (cDE) models known to fit linear observables. To implement the PS-ST approach, we start from reviewing and extending the results of a previous work on the growth of a spherical top-hat fluctuation in cDE models, confirming their most intriguing astrophysical feature, i.e. a significant baryon-DM segregation, occurring well before the onset of any hydrodynamical effect. Accordingly, the predicted mass function depends on how halo masses are measured. For any option, however, the coupling causes a distortion of the mass function, still at z = 0. Furthermore, the z-dependence of cDE mass functions is mostly displaced, in respect to ΛCDM, in the opposite way of uncoupled dynamical DE. This is an aspect of the basic underlying result, that even a little DM-DE coupling induces relevant modifications in the non-linear evolution. Therefore, without causing great shifts in linear astrophysical observables, the DM-baryon segregation induced by the coupling can have an impact on a number of cosmological problems, e.g., galaxy satellite abundance, spiral disk formation, apparent baryon shortage, entropy input in clusters, etc..

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“…An alternative option is that only DM dynamics is modified, as occurs in "ordinary" coupled DE theories. Also this option has been widely debated, N-body simulations of these models have been performed since several years (Macciò et al 2004;Baldi et al 2010;Li & Barrow 2011;Baldi 2012), finding that baryon distribution would also change, over very large scales, as an indirect consequence. Since a few years these models have been shown to be consistent with data if β ∼ < 0.1 , limits being widened if coupling is considered together with a non-vanishing neutrino mass, even finding a ∼ 2-σ constraint on the coupling β about ∼ 0.09 (La Vacca et al 2009;Kristiansen et al 2010;Pettorino et al 2012).…”

Section: Discussionmentioning

confidence: 99%

“…however, is also widely considered in the literature (see, e.g., Ellis et al (1989);Wetterich (1995); Amendola (1999); Amendola & Tocchini-Valentini (2002); Macciò et al (2004); Baldi et al (2010)), together with other possible options for energy transfer between DM and DE (see, e.g., Lopez Honorez et al (2010)). The coupling…”

Section: Coupled Dark Energy In the Early Universementioning

confidence: 99%

Strongly coupled dark energy cosmologies: preservingΛCDM success and easing low scale problems – I. Linear theory revisited

Bonometto¹,

Mainini

Macciò

2015

Mon. Not. R. Astron. Soc.

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In this first paper we discuss the linear theory and the background evolution of a new class of models we dub SCDEW: Strongly Coupled DE, plus WDM. In these models, WDM dominates today's matter density; like baryons, WDM is uncoupled. Dark Energy is a scalar field Φ; its coupling to ancillary CDM, whose today's density is ≪ 1 %, is an essential model feature. Such coupling, in fact, allows the formation of cosmic structures, in spite of very low WDM particle masses (∼ 100 eV). SCDEW models yields Cosmic Microwave Background and linear Large Scale features substantially undistinguishable from ΛCDM, but thanks to the very low WDM masses they strongly alleviate ΛCDM issues on small scales, as confirmed via numerical simulations in the II associated paper. Moreover SCDEW cosmologies significantly ease the coincidence and fine tuning problems of ΛCDM and, by using a field theory approach, we also outline possible links with inflationary models. We also discuss a possible fading of the coupling at low redshifts which prevents non linearities on the CDM component to cause computational problems. The (possible) low-z coupling suppression, its mechanism, and its consequences are however still open questions -not necessarily problems-for SCDEW models. The coupling intensity and the WDM particle mass, although being extra parameters in respect to ΛCDM , are found to be substantially constrained a priori so that, if SCDEW is the underlying cosmology, we expect most data to fit also ΛCDM predictions.

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Coupled dark energy: Parameter constraints fromN-body simulations

Cited by 164 publications

References 29 publications

Nonlinear evolution off(R)cosmologies. II. Power spectrum

Nonlinear evolution off(R)cosmologies. II. Power spectrum

Mass functions in coupled dark energy models

Strongly coupled dark energy cosmologies: preservingΛCDM success and easing low scale problems – I. Linear theory revisited

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