scholarly journals Testing the consistency between cosmological data: the impact of spatial curvature and the dark energy EoS

2021 ◽  
Vol 2021 (11) ◽  
pp. 060
Author(s):  
Javier E. Gonzalez ◽  
Micol Benetti ◽  
Rodrigo von Marttens ◽  
Jailson Alcaniz
Keyword(s):  
Dark Energy ◽  
Joint Analysis ◽  
Data Sets ◽  
Acoustic Oscillations ◽  
Spatial Curvature ◽  
Eos Parameter ◽  
Flat Universe ◽  
Type Ia ◽  
Cosmological Data ◽  
The Impact

Abstract The results of joint analyses of available cosmological data have motivated an important debate about a possible detection of a non-zero spatial curvature. If confirmed, such a result would imply a change in our present understanding of cosmic evolution with important theoretical and observational consequences. In this paper we discuss the legitimacy of carrying out joint analyses with the currently available data sets and explore their implications for a non-flat universe and extensions of the standard cosmological model. We use a robust tension estimator to perform a quantitative analysis of the physical consistency between the latest data of Cosmic Microwave Background, type Ia supernovae, Baryonic Acoustic Oscillations and Cosmic Chronometers. We consider the flat and non-flat cases of the ΛCDM cosmology and of two dark energy models with a constant and varying dark energy EoS parameter. The present study allows us to better understand if possible inconsistencies between these data sets are significant enough to make the results of their joint analyses misleading, as well as the actual dependence of such results with the spatial curvature and dark energy parameterizations. According to our results, we conclude that a joint analysis in the context of a non-flat universe including the CMB data is only possible if the CMB Lens is taken into account, otherwise, it potentially leads to misleading conclusions.

scholarly journals Bayesian comparison of interacting modified holographic Ricci dark energy scenarios

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
Antonella Cid ◽  
Carlos Rodriguez-Benites ◽  
Mauricio Cataldo ◽  
Gonzalo Casanova
Keyword(s):  
Dark Energy ◽  
Hubble Constant ◽  
Joint Analysis ◽  
Acoustic Oscillations ◽  
Microwave Background ◽  
Ricci Dark Energy ◽  
Type Ia ◽  
Cosmological Data ◽  
Ia Supernovae ◽  
Local Value

AbstractWe perform a Bayesian model selection analysis for interacting scenarios of dark matter and modified holographic Ricci dark energy (MHRDE) with linear interacting terms. We use a combination of some of the latest cosmological data such as type Ia supernovae, cosmic chronometers, the local value of the Hubble constant, baryon acoustic oscillations measurements and cosmic microwave background through the angular scale of the sound horizon at last scattering. We find moderate/strong evidence against all the MHRDE interacting scenarios studied with respect to $$\Lambda $$ Λ CDM when the full joint analysis is considered.

scholarly journals Measurements of $$H_0$$ and reconstruction of the dark energy properties from a model-independent joint analysis

2021 ◽  
Vol 81 (2) ◽  
Author(s):  
Alexander Bonilla ◽  
Suresh Kumar ◽  
Rafael C. Nunes
Keyword(s):  
Dark Energy ◽  
Sound Speed ◽  
Hubble Constant ◽  
State Parameter ◽  
Independent Method ◽  
Joint Analysis ◽  
Acoustic Oscillations ◽  
Type Ia ◽  
Model Independent ◽  
Supernova Type Ia

AbstractGaussian processes (GP) provide an elegant and model-independent method for extracting cosmological information from the observational data. In this work, we employ GP to perform a joint analysis by using the geometrical cosmological probes such as Supernova Type Ia (SN), Cosmic chronometers (CC), Baryon Acoustic Oscillations (BAO), and the H0LiCOW lenses sample to constrain the Hubble constant $$H_0$$ H 0 , and reconstruct some properties of dark energy (DE), viz., the equation of state parameter w, the sound speed of DE perturbations $$c^2_s$$ c s 2 , and the ratio of DE density evolution $$X = \rho _\mathrm{de}/\rho _\mathrm{de,0}$$ X = ρ de / ρ de , 0 . From the joint analysis SN+CC+BAO+H0LiCOW, we find that $$H_0$$ H 0 is constrained at 1.1% precision with $$H_0 = 73.78 \pm 0.84\ \hbox {km}\ \hbox {s}^{-1}\,\hbox {Mpc}^{-1}$$ H 0 = 73.78 ± 0.84 km s - 1 Mpc - 1 , which is in agreement with SH0ES and H0LiCOW estimates, but in $$\sim 6.2 \sigma $$ ∼ 6.2 σ tension with the current CMB measurements of $$H_0$$ H 0 . With regard to the DE parameters, we find $$c^2_s < 0$$ c s 2 < 0 at $$\sim 2 \sigma $$ ∼ 2 σ at high z, and the possibility of X to become negative for $$z > 1.5$$ z > 1.5 . We compare our results with the ones obtained in the literature, and discuss the consequences of our main results on the DE theoretical framework.

scholarly journals AGEGRAPHIC DARK ENERGY MODEL IN THE NON-FLAT UNIVERSE: STATEFINDER DIAGNOSTIC AND w–w′ ANALYSIS

2010 ◽  
Vol 19 (11) ◽  
pp. 1857-1871 ◽  
Author(s):  
M. MALEKJANI ◽  
A. KHODAM-MOHAMMADI
Keyword(s):  
Dark Energy ◽  
Accelerated Expansion ◽  
Model Parameters ◽  
Closed Universe ◽  
Statefinder Parameters ◽  
Spatial Curvature ◽  
Eos Parameter ◽  
Agegraphic Dark Energy ◽  
Flat Universe ◽  
Evolutionary Trajectories

We study the interacting agegraphic dark energy (ADE) model in the non-flat universe by means of the statefinder diagnostic and an w–w′ analysis. First, the evolution of EoS parameter (wd) and deceleration parameter (q) are calculated in terms of scale-factor for interacting ADE models in the non-flat universe. The dependency of wd on the ADE model parameters n and α in different spatial curvatures is investigated. We show that the evolution of q is dependent on the type of spatial curvature, besides dependening on parameters n and α. The accelerated expansion takes place sooner in the open universe and latter in the closed universe as compared with the flat universe. Then, we plot the evolutionary trajectories of the interacting ADE models for different values of the parameters n and α, as well as for different contributions of spatial curvature, in the plane of statefinder parameters. In addition to the statefinder, we also investigate the ADE model in the non-flat universe with w–w′ analysis.

scholarly journals Low-redshift constraints on covariant canonical Gauge theory of gravity

2021 ◽  
Vol 81 (2) ◽  
Author(s):  
David Benisty ◽  
David Vasak ◽  
Johannes Kirsch ◽  
Jürgen Struckmeier
Keyword(s):  
Deformation Parameter ◽  
Data Sets ◽  
Acoustic Oscillations ◽  
Spatial Curvature ◽  
Stress Energy ◽  
Type Ia ◽  
Ia Supernovae ◽  
Gauge Gravity ◽  
Gauge Theory Of Gravity ◽  
Combined Data

AbstractConstraints on the Covariant Canonical Gauge Gravity (CCGG) theory from low-redshift cosmology are studied. The formulation extends Einstein’s theory of General Relativity (GR) by a quadratic Riemann–Cartan term in the Lagrangian, controlled by a “deformation” parameter. In the Friedman universe this leads to an additional geometrical stress energy and promotes, due to the necessary presence of torsion, the cosmological constant to a time-dependent function. The MCMC analysis of the combined data sets of Type Ia Supernovae, Cosmic Chronometers and Baryon Acoustic Oscillations yields a fit that is well comparable with the $$\Lambda $$ Λ CDM results. The modifications implied in the CCGG approach turn out to be subdominant in the low-redshift cosmology. However, a non-zero spatial curvature and deformation parameter are shown to be consistent with observations.

scholarly journals Consistency of nonlinear interacting ghost dark energy with recent observations

2017 ◽  
Vol 26 (11) ◽  
pp. 1750124 ◽  
Author(s):  
E. Ebrahimi ◽  
H. Golchin ◽  
A. Mehrabi ◽  
S. M. S. Movahed
Keyword(s):  
Dark Energy ◽  
Observational Data ◽  
Nonlinear Interaction ◽  
Acoustic Oscillation ◽  
Joint Analysis ◽  
Data Sets ◽  
Dark Energy Density ◽  
Ghost Dark Energy ◽  
Interaction Terms ◽  
Best Fit

In this paper, we investigate ghost dark energy model in the presence of nonlinear interaction between dark energy and dark matter. We also extend the analysis to the so-called generalized ghost dark energy (GGDE) which [Formula: see text]. The model contains three free parameters as [Formula: see text] and [Formula: see text] (the coupling coefficient of interactions). We propose three kinds of nonlinear interaction terms and discuss the behavior of equation of state, deceleration and dark energy density parameters of the model. We also find the squared sound speed and search for signs of stability of the model. To compare the interacting GGDE model with observational data sets, we use more recent observational outcomes, namely SNIa from JLA catalog, Hubble parameter, baryonic acoustic oscillation and the most relevant CMB parameters including, the position of acoustic peaks, shift parameters and redshift to recombination. For GGDE with the first nonlinear interaction, the joint analysis indicates that [Formula: see text], [Formula: see text] and [Formula: see text] at 1 optimal variance error. For the second interaction, the best fit values at [Formula: see text] confidence are [Formula: see text], [Formula: see text] and [Formula: see text]. According to combination of all observational data sets considered in this paper, the best fit values for third nonlinearly interacting model are [Formula: see text], [Formula: see text] and [Formula: see text] at [Formula: see text] confidence interval. Finally, we found that the presence of interaction is compatible in mentioned models via current observational datasets.

scholarly journals Cosmological constraints from H ii starburst galaxy apparent magnitude and other cosmological measurements

2020 ◽  
Vol 497 (3) ◽  
pp. 3191-3203 ◽  
Author(s):  
Shulei Cao ◽  
Joseph Ryan ◽  
Bharat Ratra
Keyword(s):  
Dark Energy ◽  
Cosmological Parameters ◽  
Angular Size ◽  
Hubble Constant ◽  
Joint Analysis ◽  
Apparent Magnitude ◽  
Starburst Galaxy ◽  
Density Parameter ◽  
Acoustic Oscillations ◽  
Combined Data

ABSTRACT We use H ii starburst galaxy apparent magnitude measurements to constrain cosmological parameters in six cosmological models. A joint analysis of H ii galaxy, quasar angular size, baryon acoustic oscillations peak length scale, and Hubble parameter measurements result in relatively model-independent and restrictive estimates of the current values of the non-relativistic matter density parameter $\Omega _{\rm m_0}$ and the Hubble constant H0. These estimates favour a 2.0–3.4σ (depending on cosmological model) lower H0 than what is measured from the local expansion rate. The combined data are consistent with dark energy being a cosmological constant and with flat spatial hypersurfaces, but do not strongly rule out mild dark energy dynamics or slightly non-flat spatial geometries.

scholarly journals Constraints on barotropic dark energy models by a new phenomenological q(z) parameterization

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
Jaime Román-Garza ◽  
Tomás Verdugo ◽  
Juan Magaña ◽  
Verónica Motta
Keyword(s):  
Dark Energy ◽  
Joint Analysis ◽  
Effective Equation ◽  
Phantom Divide ◽  
Plane Analysis ◽  
Energy Models ◽  
A Value ◽  
Type Ia ◽  
Ia Supernovae ◽  
The Universe

Abstract In this paper, we propose a new phenomenological two parameter parameterization of q(z) to constrain barotropic dark energy models by considering a spatially flat Universe, neglecting the radiation component, and reconstructing the effective equation of state (EoS). This two free-parameter EoS reconstruction shows a non-monotonic behavior, pointing to a more general fitting for the scalar field models, like thawing and freezing models. We constrain the q(z) free parameters using the observational data of the Hubble parameter obtained from cosmic chronometers, the joint-light-analysis Type Ia Supernovae (SNIa) sample, the Pantheon (SNIa) sample, and a joint analysis from these data. We obtain, for the joint analysis with the Pantheon (SNIa) sample a value of q(z) today, $$q_0=-0.51\begin{array}{c} +0.09 \\ -0.10 \end{array}$$q0=-0.51+0.09-0.10, and a transition redshift, $$z_t=0.65\begin{array}{c} +0.19 \\ -0.17 \end{array}$$zt=0.65+0.19-0.17 (when the Universe change from an decelerated phase to an accelerated one). The effective EoS reconstruction and the $$\omega '$$ω′–$$\omega $$ω plane analysis point towards a transition over the phantom divide, i.e. $$\omega =-1$$ω=-1, which is consistent with a non parametric EoS reconstruction reported by other authors.

scholarly journals A divergence-free parametrization of deceleration parameter for scalar field dark energy

2016 ◽  
Vol 25 (03) ◽  
pp. 1650032 ◽  
Author(s):  
Abdulla Al Mamon ◽  
Sudipta Das
Keyword(s):  
Dark Energy ◽  
Deceleration Parameter ◽  
Acoustic Oscillations ◽  
Microwave Background ◽  
Frw Universe ◽  
Potential Term ◽  
Type Ia ◽  
De Formula ◽  
Divergence Free ◽  
Baryonic Acoustic Oscillations

In this paper, we have considered a spatially flat FRW universe filled with pressureless matter and dark energy (DE). We have considered a phenomenological parametrization of the deceleration parameter [Formula: see text] and from this, we have reconstructed the equation-of-state (EoS) for DE [Formula: see text]. This divergence-free parametrization of the deceleration parameter is inspired from one of the most popular parametrization of the DE EoS given by Barboza and Alcaniz [see E. M. Barboza and J. S. Alcaniz, Phys. Lett. B 666 (2008) 415]. Using the combination of datasets (Type Ia Supernova (SN Ia) + Hubble + baryonic acoustic oscillations/cosmic microwave background (BAO/CMB)), we have constrained the transition redshift [Formula: see text] (at which the universe switches from a decelerating to an accelerating phase) and have found the best fit value of [Formula: see text]. We have also compared the reconstructed results of [Formula: see text] and [Formula: see text] and have found that the results are compatible with a [Formula: see text]CDM universe if we consider SN Ia + Hubble data, but inclusion of BAO/CMB data makes [Formula: see text] and [Formula: see text] incompatible with [Formula: see text]CDM model. The potential term for the present toy model is found to be functionally similar to a Higgs potential.

scholarly journals Probing dark energy with braneworld cosmology in the light of recent cosmological data

2018 ◽  
Vol 27 (02) ◽  
pp. 1850006 ◽  
Author(s):  
Miguel A. García-Aspeitia ◽  
Juan Magaña ◽  
A. Hernández-Almada ◽  
V. Motta
Keyword(s):  
Dark Energy ◽  
Background Radiation ◽  
Big Bang ◽  
Accelerated Expansion ◽  
Joint Analysis ◽  
Brane Tension ◽  
Acoustic Oscillations ◽  
Brane Model ◽  
Baryon Acoustic Oscillations ◽  
The Universe

We investigate a brane model based on Randall–Sundrum scenarios with a generic dark energy component. The latter drives the accelerated expansion at late-times of the universe. In this scheme, extra terms are added into Einstein Field equations that are propagated to the Friedmann equations. To constrain the dark energy equation-of-state (EoS) and the brane tension we use observational data with different energy levels (Supernovae Type Ia, [Formula: see text], baryon acoustic oscillations, and cosmic microwave background radiation distance, and a joint analysis) in a background cosmology. Beside EoS being consistent with a cosmological constant at the [Formula: see text] confidence level for each dataset, the baryon acoustic oscillations probe favors an EoS consistent with a quintessence dark energy. Although we found different lower limit bounds on the brane tension for each dataset, being the most restricted for CMB, there is not enough evidence of modifications in the cosmological evolution of the universe by the existence of an extra dimension within observational uncertainties. Nevertheless, these new bounds are complementary to those obtained by other probes like table-top experiments, Big Bang Nucleosynthesis, and stellar dynamics. Our results show that a further test of the braneworld model with appropriate correction terms or a profound analysis with perturbations, may be needed to improve the constraints provided by the current data.

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