Astronomical bounds on the modified Chaplygin gas as a unified dark fluid model

Li, Hang; Yang, Weiqiang; Gai, L L

doi:10.1051/0004-6361/201833836

Cited by 11 publications

(11 citation statements)

References 66 publications

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“…This result should not be naively interpreted as suggesting that a three-parameter model like the modified Chaplygin gas of (5) performs better than the Chaplygin gas just because it involves two more free parameters which can be appropriately tuned, but it is a genuinely physical result. We would like to mention as well that this is not the first time that a negative value of α is estimated: see for example [120,121] where Planck 2015, type-Ia supernovae, and Hubble parameter data are used. In this paper we found that assuming the dark sector to be composed by two components interacting with each other, our estimates deviate more from the Chaplygin gas behavior than the ones in this previous investigation.…”

Section: Discussionmentioning

confidence: 99%

Constraints on interacting dark energy models through cosmic chronometers and Gaussian process

2021

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In this paper, after reconstructing the redshift evolution of the Hubble function by adopting Gaussian process techniques, we estimate the best-fit parameters for some flat Friedmann cosmological models based on a modified Chaplygin gas interacting with dark matter. In fact, the expansion history of the Universe will be investigated because passively evolving galaxies constitute cosmic chronometers. An estimate for the present-day values of the deceleration parameter, adiabatic speed of sound within the dark energy fluid, effective dark energy, and dark matter equation of state parameters is provided. By this, we mean that the interaction term between the two dark fluids, which breaks the Bianchi symmetries, will be interpreted as an effective contribution to the dark matter pressure similarly to the framework of the “Generalized Dark Matter”. We investigate whether the estimates of the Hubble constant and of the present-day abundance of dark matter are sensitive to the dark matter–dark energy coupling. We will also show that the cosmic chronometers data favor a cold dark matter, and that our findings are in agreement with the Le Châtelier–Braun principle according to which dark energy should decay into dark matter.

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Section: Discussionmentioning

confidence: 99%

Constraints on interacting dark energy models through cosmic chronometers and Gaussian process

2021

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“…Every dark energy or unified dark matter energy-momentum tensor can be remapped into vacuum interacting with CDM (Wands et al 2012). However, especially in the case of unified dark matter, these models are often subject to severe observational constraints because of the speed of sound of the dark component (Sandvik et al 2004), see also Balbi et al (2007); Pietrobon et al (2008); Piattella et al (2010); Piattella (2010); Gao et al (2010); Bertacca et al (2011);De Felice et al (2012); Wang et al (2013); Li et al (2018Li et al ( , 2019; an advantage of the interacting vacuum formulation is that vacuum does not cluster and, in the specific sub-case of a pure energy exchange we consider here (no momentum exchange in the rest frame of CDM) CDM remains geodesic, as in ΛCDM. The generalised Chaplygin gas dark energy model was reconsidered in this fashion by Bento et al (2004) and Wands et al (2012), and Wang et al (2013) considered observational constraints on the same.…”

Section: Discussionmentioning

confidence: 99%

“…However, serious objections to the Chaplygin gas model were raised when it was found that unified models of this type result in oscillations or an exponential blow-up in the matter power spectrum, thus ruling out the vast majority of the viable Chaplygin gas model space (Sandvik et al 2004). To counter this, further models in which dark matter transitions to dark energy via a condensation mechanism have been proposed and studied, and interest in unified models of this type remains high -see, for example, Balbi et al (2007); Pietrobon et al (2008); Piattella et al (2010); Piattella (2010); Gao et al (2010); Bertacca et al (2011);De Felice et al (2012); Wang et al (2013); Li et al (2018Li et al ( , 2019.…”

Section: Introductionmentioning

confidence: 99%

Shan--Chen interacting vacuum cosmology

Hogg,

Bruni

2021

Preprint

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In this paper we introduce a novel class of interacting vacuum models, based on recasting the equation of state originally developed in the context of lattice kinetic theory by Shan & Chen (1993) as the coupling between the vacuum and cold dark matter (CDM). This coupling allows the vacuum to evolve and is nonlinear around a characteristic energy scale 𝜌 * , changing into a linear coupling with a typical power law evolution at scales much lower and much higher than 𝜌 * . Focusing on the simplest sub-class of models where the interaction consists only of an energy exchange and the CDM remains geodesic, we first illustrate the various possible models that can arise from the Shan-Chen coupling, with several different behaviours at both early and late times depending on the values of the model parameters selected. We then place the first observational constraints on this Shan-Chen interacting vacuum scenario, performing an MCMC analysis to find those values of the model and cosmological parameters which are favoured by observational data. In doing so we focus on models where the nonlinearity of the coupling is relevant at late times, choosing for the reference energy scale 𝜌 * the critical energy density in ΛCDM. We show that the observational data we use (cosmic microwave background temperature and polarisation, baryon acoustic oscillation and type Ia supernovae measurements) are compatible with a wide range of models which result in very different cosmologies. However, we also show that ΛCDM is preferred over all but one of the Shan-Chen interacting vacuum models that we study, and comment on the inability of these models to relax the 𝐻 0 and 𝜎 8 tensions.

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“…The MCG model is also a unified dark matter and dark energy model, which is a modification of the GCG model. It has been widely discussed in many perspectives [58][59][60][61][62][63]. This class of equation of state is expressed as,…”

Section: Mcg Modelmentioning

confidence: 99%

Revisiting Chaplygin gas cosmologies with the recent observations of high-redshift quasars

et al. 2022

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In this paper, we use the latest observations of quasars covering the redshift range of $$0.04<z<5.1$$ 0.04 < z < 5.1 to investigate a series of Chaplygin gas models as candidates for unified dark matter and dark energy. Based on different combinations of available standard candle and standard ruler data, we put constraints on the generalized Chaplygin gas (GCG), modified Chaplygin gas (MCG), new generalized Chaplygin gas (NGCG) and viscous generalized Chaplygin gas (VGCG) models. Moreover, we apply Jensen–Shannon divergence (JSD), statefinder diagnostics, and the deviance information criterion (DIC) to distinguish these CG models, based on the statistical results derived from Markov chain Monte Carlo method. The results show that (1) The standard ruler data could provide more stringent constraints on the cosmological parameters of different CG models considered in this analysis. Interestingly, the matter density parameter $$\varOmega _{m}$$ Ω m and Hubble constant $$H_{0}$$ H 0 derived from the available data are well consistent with those from the Planck 2018 results; (2) Based on the statistical criteria JSD, our findings demonstrate the well consistency between Chaplygin gas and the concordance $$\varLambda $$ Λ CDM model. However, in the framework of statefinder diagnostics, the GCG and NGCG models cannot be distinguished from $$\varLambda $$ Λ CDM, while MCG and VGCG models show significant deviation from $$\varLambda $$ Λ CDM in the present epoch; (3) According to the the statistical criteria DIC, we show that the MCG and VGCG models have substantial observational support from high-redshift quasars, whereas the GCG and NGCG models miss out on the less observational support category but can not be ruled out.

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Astronomical bounds on the modified Chaplygin gas as a unified dark fluid model

Cited by 11 publications

References 66 publications

Constraints on interacting dark energy models through cosmic chronometers and Gaussian process

Constraints on interacting dark energy models through cosmic chronometers and Gaussian process

Shan--Chen interacting vacuum cosmology

Revisiting Chaplygin gas cosmologies with the recent observations of high-redshift quasars

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