Related papers: Observational constraint on dynamical evolution of…
The equation of state characterizing the dark energy component is constrained by combining Chandra observations of the X-ray luminosity of galaxy clusters with independent measurements of the baryonic matter density and the latest…
We study a cosmological model featuring evolutionary dark energy, according to the idea that the creation of its constituents arises from the gravitational field of the expanding universe, whose non-equilibrium physics is described by a…
We introduce a minimal two-parameter formulation of the dark energy (DE) density evolution normalized to its present-day value, $f_{\rm DE}(z) \equiv \rho_{\rm DE}(z)/\rho_{\rm DE,0}$, in terms of $f_p\equiv f_{\rm DE}(z_p)$ and the DE…
The explanation of the accelerated expansion of the Universe poses one of the most fundamental questions in physics and cosmology today. If the acceleration is driven by some form of dark energy, one can try to constrain the parameters…
We present a best-fit analysis on the single-parameter holographic dark energy model characterized by the conformal-age-like length, $L=\frac{1}{a^4(t)}\int_0^tdt' a^3(t') $. Based on the Union2 compilation of 557 supernova Ia data, the…
We use the latest compilation of observational H(z) measurements obtained with cosmic chronometers in the redshift range $0<z<2$ to place constraints on cosmological parameters. We consider the sample alone and in combination with other…
In this paper, we study a cosmological model in general relativity within the framework of spatially flat Friedmann-Robertson-Walker space-time filled with ordinary matter (baryonic), radiation, dark matter and dark energy, where the latter…
We reconsider the holographic dark energy (HDE) model with a slowly time varying $ c^2(z)$ parameter in the energy density, namely $\rho_D=3M_p^2 c^2(z)/L^2$, where $L$ is the IR cutoff and $z$ is the redshift parameter. As the system's IR…
We present a Bayesian comparative analysis of five cosmological models: $\Lambda$CDM, $w$CDM, $w_0w_a$CDM, $\phi$CDM (with scalar-field dark energy), and an interacting dark energy scenario (the $\xi$-index model), to investigate dark…
We have improved upon the method of smoothing supernovae data to reconstruct the expansion history of the universe, h(z), using two latest datasets, Gold and SNLS. The reconstruction process does not employ any parameterization and is…
We use the Simon, Verde, & Jimenez (2005) determination of the redshift dependence of the Hubble parameter to constrain cosmological parameters in three dark energy cosmological models. We consider the standard $\Lambda$CDM model, the XCDM…
In this note we investigate the effects of perturbations in a dark energy component with a constant equation of state on large scale cosmic microwave background anisotropies. The inclusion of perturbations increases the large scale power.…
In this work we explore signatures of evolution for the dark energy density $X(z)=\rho_{de}(z)/\rho_{de}(0)$ using latest observations on SNIa and H(z). The models consist of parametrizations of the dark energy density and consequently a…
In the present paper, we investigate the dark energy equation of state using the Gaussian processes analysis method, without confining a particular parametrization. The reconstruction is carried out by adopting the background data including…
We present new constraints on extended cosmological scenarios using the recent data from the Planck 2018 Legacy release. In addition to the six parameters of the standard LCDM model, we also simultaneously vary the dark energy equation of…
In this paper, we use the joint measurement of geometry and growth rate from matter density perturbations to constrain the holographic dark energy model. The geometry measurement includes type Ia supernovae (SN Ia) Union2.1, full…
We consider a model-independent approach to constrain the equivalence redshift, $z_{eq}$, at which dark energy and the total matter (cold dark matter and baryonic) equate their magnitudes. To this aim, in the context of a homogeneous and…
We have studied constraints on the equation of state, $w$, and speed of sound, c_s, of the dark energy from a joint analysis of data from the cosmic microwave background, large scale structure and type-Ia supernovae. We find that current…
We investigate the cosmological implications of a generalized total equation of state (EoS) model by constraining its parameters using observational datasets to effectively characterize the universe's expansion history and its dynamic…
We constrain the dark energy equation of state parameter, $w$, using the power spectrum of the thermal Sunyaev-Zeldovich (tSZ) effect. We improve upon previous analyses by taking into account the trispectrum in the covariance matrix and…