Hubble Data Research Articles

Oscillating Dark Energy in Light of the Latest Observations and Its Impact on the Hubble Tension

In this paper, we have performed a comparative study of different types of oscillating dark energy (DE) models using the Metropolis algorithm of Markov Chain Monte Carlo. Eight different oscillating parameterizations are examined herein that have demonstrated considerable ability to fit the overall cosmological observations, including the Pantheon sample of Type Ia supernovae, baryon acoustic oscillations, cosmic chronometer Hubble data, and distance priors of the Planck cosmic microwave background. In order to compare the consistency of these models with observations, we have used both the Akaike and deviance information criteria. Although the values of the Akaike information criterion for different models indicate that there is no support for oscillating DE models, the deviance information criterion showed that there is significant support for some of these models. Our results showed that these models are capable of solving the cosmic coincidence problem and alleviating the Hubble tension. Comparing the H 0 values obtained for different oscillating scenarios with that of ΛCDM, we observed that our oscillating models led to H0¯=69.78 , which is 0.29 greater than H 0,Λ and thus reduces the Hubble tension. Among all of the models, model 1, with H 0 = 70.00 ± 0.71, is the most capable of alleviating the H 0 tension. Furthermore, we examined our models assuming H 0 = 73.0 ± 1.4 from SHoES measurements. We find that adding this data point to our data combination led to a ΔH0¯=0.95 increase in the H 0 value for different models.

Model-independent test of the running Hubble constant from the Type Ia supernovae and the Hubble parameter data

ABSTRACT In this study, we model-independently investigate the behaviour of running Hubble constant, characterized by the fit function $H_{\rm 0}(z)=\tilde{H_{\rm {0}}}/(1+z)^{\alpha }$, where α represents the evolutionary parameter and ${\tilde{H_{\rm {0}}}}$ corresponds to the current value of Hubble constant. Our analysis utilizes the expansion rate E(z) data points measured from the Pantheon + Multi-Cycle Treasury compilation of Type Ia supernova data, the measurements of H0 obtained by Riess et al., and the Hubble parameter H(z) data obtained from the differential ages of passive galaxies [known as cosmic chronometer (CC) method] and from the baryon acoustic oscillation (BAO) in the radial direction of galaxy clustering. To resolve the redshift mismatch problem between the E(z) and H(z) data sets, we adopt the Hubble parameter data obtained via CC or BAO along with the measurements of H0 obtained by Riess et al. to reconstruct the H(z) function using the Gaussian process. Our constraint yields α values of 0.125 ± 0.063 or 0.095 ± 0.052 when combining six pairs of the E(z) data and the reconstructed H(z) points via CC or BAO. These findings reveal that the Hubble constant may evolve with redshift, exhibiting a slowly decreasing trend, with α coefficients consistent with zero only at 2.0σ or 1.8σ. Therefore, the running Hubble constant might offer a promising resolution to the Hubble tension, and its reliability should be further tested through high-precision measurement at higher redshifts, such as the upcoming gamma-ray bursts and quasars.

Revisiting kink-like parametrization and constraints using OHD/Pantheon+/BAO samples

We reexamine the kink-like parametrization of the deceleration parameter to derive constraints on the transition redshift from cosmic deceleration to acceleration. This is achieved using observational Hubble data, Type Ia Supernovae Pantheon+ samples and Baryon acoustic oscillations. In this parametrization, the value of the initial q parameter is qi, the final value is qf, the present value is denoted by q0, and the transition duration is given by α. We perform our calculations using the Monte Carlo Markov Chain method, utilizing the emcee package. Under the assumption of a flat geometry, we constrain the range of possible values for three scenarios: when qf is unrestricted, when qf is equal to −1, and when α is 1/3. This is done assuming that qi=1/2. Here, we achieve that the SN data fixes the free parameters tightly as in the flat ΛCDM for unrestricted qf. In addition, if we fix qf=−1, the model behaves well as the ΛCDM for the combined dataset. We also acquire the current value of the deceleration parameter, which is consistent with the latest results that assume the ΛCDM model. Furthermore, we observe a deviation from the standard ΛCDM model in the current model based on the evolution of j(z), and it is evident that the universe transitions from deceleration to acceleration and will eventually reach the ΛCDM model in the near future.

Constraints on cosmological models from quasars calibrated with type Ia supernova by a Gaussian process

ABSTRACT In this paper, we use quasars calibrated from type Ia supernova (SN Ia) to constrain cosmological models. We consider three different X-ray luminosity (LX)–ultraviolet luminosity (LUV) relations of quasars, i.e. the standard LX–LUV relation and two redshift–evolutionary relations (Type I and Type II), respectively, constructed from copula and considering a redshift correction to the luminosity of quasars. Only in the case of the Type I relation, quasars can always provide effective constraints on the ΛCDM (cosmological constant Λ plus cold dark matter) model. Furthermore, we show that, when the observational Hubble data (OHD) are added, the constraints on the absolute magnitude M of SN Ia and the Hubble constant H0 can be obtained. In the ΛCDM model, the OHD measurements plus quasars with the Type I relation yields M = $-19.321^{+0.085}_{-0.076}$, which is in good agreement with the measurement from SH0ES (M = −19.253 ± 0.027), and H0 = $70.80\pm 3.6~\mathrm{km~s^{-1}\, Mpc^{-1}}$, falling between the measurements from SH0ES and the Planck cosmic microwave background radiation data.

Analytical Gaussian process cosmography: unveiling insights into matter-energy density parameter at present

In this study, we introduce a novel analytical Gaussian Process (GP) cosmography methodology, leveraging the differentiable properties of GPs to derive key cosmological quantities analytically. Our approach combines cosmic chronometer (CC) Hubble parameter data with growth rate (f) observations to constrain the Ωm0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Omega _{\ extrm{m0}}$$\\end{document} parameter, offering insights into the underlying dynamics of the Universe. By formulating a consistency relation independent of specific cosmological models, we analyze under a flat FLRW metric and first-order Newtonian perturbation theory framework. Our analytical approach simplifies the process of Gaussian Process regression (GPR), providing a more efficient means of handling large datasets while offering deeper interpretability of results. We demonstrate the effectiveness of our methodology by deriving precise constraints on Ωm0h2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Omega _{\ extrm{m0}}h^2$$\\end{document}, revealing Ωm0h2=0.139±0.017\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Omega _\ extrm{m0}h^2=0.139\\pm 0.017$$\\end{document}. Moreover, leveraging H0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$H_0$$\\end{document} observations, we further constrain Ωm0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Omega _{\ extrm{m0}}$$\\end{document}, uncovering an inverse correlation between mean H0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$H_0$$\\end{document} and Ωm0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Omega _{\ extrm{m0}}$$\\end{document}. Our investigation offers a proof of concept for analytical GP cosmography, highlighting the advantages of analytical methods in cosmological parameter estimation.

Effects of particle creation rate in two-fluid interacting cosmologies

ABSTRACT In this work, a two-fluid interacting model in a flat FLRW universe has been studied considering particle creation mechanism with a particular form of particle creation rate $\Gamma =\Gamma _0 H+\frac{\Gamma _1}{H}$ from different aspects. Statistical analysis with a combined data set of SNe Ia (Supernovae Type Ia) and Hubble data is performed to achieve the best-fitting values of the model parameters, and the model is compatible with current observational data. We also perform a dynamical analysis of this model to get an overall qualitative description of the cosmological evolution by converting the governing equations into a system of ordinary differential equations considering a proper transformation of variables. We find some non-isolated sets of critical points, among which some usually are normally hyperbolic sets of points that describe the present acceleration of the universe dominated by dark energy mimicking cosmological constant or phantom fluid. Scaling solutions are also obtained from this analysis, and they can alleviate the coincidence problem successfully. Statefinder diagnosis is also carried out for this model to compare it with the ΛCDM, and any other dark energy models byfinding various statefinder parameters. Finally, the thermodynamic analysis shows that the generalized second law of thermodynamics is valid in an irreversible thermodynamic context.

Putting flat [formula omitted]CDM in the (Redshift) bin

Flat ΛCDM cosmology is specified by two constant fitting parameters at the background level in the late Universe, the Hubble constant H0 and matter density (today) Ωm. Mathematically, H0 and Ωm are either integration constants arising from solving ordinary differential equations or are directly related to integration constants. Seen in this context, if fits of the ΛCDM model to cosmological probes at different redshifts lead to different (H0,Ωm) parameters, this is a mismatch between mathematics and observation. Here, in mock observational Hubble data (OHD) (geometric probes of expansion history) we demonstrate evolution in distributions of best fit parameters with effective redshift. As a result, considerably different (H0,Ωm) best fits from Planck-ΛCDM cannot be precluded in high redshift bins. We explore if OHD, Type Ia supernovae and standardisable quasar samples exhibit redshift evolution of best fit ΛCDM parameters. In all samples, we confirm a decreasing H0 and increasing Ωm trend with increasing bin redshift. Through comparison with mocks, we confirm that similar behaviour can arise randomly within the flat ΛCDM model with probabilities as low as p=0.0021 (3.1σ). We present complementary profile distribution analysis confirming the shifts in cosmological parameters in high redshift bins. In particular, we identify a redshift range where Planck (H0,Ωm) values are disfavoured at 99.6% (2.9σ) confidence level in a combination of OHD and supernovae data.

Lyman Continuum Emission from Active Galactic Nuclei at 2.3 ≲ z ≲ 3.7 in the UVCANDELS Fields

We present the results of our search for Lyman continuum (LyC)-emitting (weak) active galactic nuclei (AGN) at redshifts 2.3 ≲ z ≲ 4.9 from Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) F275W observations in the Ultraviolet Imaging of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (UVCANDELS) fields. We also include LyC emission from AGN using HST WFC3 F225W, F275W, and F336W imaging found in Early Release Science (ERS) and Hubble Deep UV Legacy Survey data. We performed exhaustive queries of the Vizier database to locate AGN with high-quality spectroscopic redshifts. In total, we found 51 AGN that met our criteria within the UVCANDELS and ERS footprints. Out of these 51, we find 12 AGN that had ≥4σ detected LyC flux in the WFC3/UVIS images. Using a wide variety of space-based plus ground-based data, ranging from X-ray to radio wavelengths, we fit the multiwavelength photometric data of each AGN to a CIGALE spectral energy distribution (SED) using AGN models and correlate various SED parameters to the LyC flux. Kolmogorov–Smirnov tests of the SED parameter distributions for the LyC-detected and nondetected AGN showed they are likely not distinct samples. However, we find that the X-ray luminosity, star formation onset age, and disk luminosity show strong correlations relative to their emitted LyC flux. We also find strong correlations of the LyC flux to several dust parameters, i.e., polar and toroidal dust emission and 6 μm luminosity, and anticorrelations with metallicity and A FUV. We simulate the LyC escape fraction (f esc) using the CIGALE and intergalactic medium transmission models for the LyC-detected AGN and find an average f esc ≃ 18%, weighted by uncertainties. We stack the LyC fluxes of subsamples of AGN according to the wavelength continuum region in which they are detected and find no significant distinctions in their LyC emission, although our submillimeter-detected F336W sample (3.15 < z < 3.71) shows the brightest stacked LyC flux. These findings indicate that LyC production and escape in AGN are more complicated than the simple assumption of thermal emission and a 100% escape fraction. Further testing of AGN models with larger samples than presented here is needed.

Two forms of dark energy in fractal cosmological model using specific Hubble parameter

The main objective of this article is to study the fractal FRW cosmological model consisting two forms of dark energy. We studied behavior of the universe in a fractal framework using dark energy accommodated in our universe. The solution of field equations are obtained by using Hubble parameter for transit scale factor H(z)=ϵa−δ+λ . We have obtained the best fitting values of the model parameters ϵ,δ and λ by constraining our model with latest Hubble and SNe-Ia data sets . Finally we perform state-finder diagnosis and observe that obtained model close to standard ΛCDM model.

Cosmic expansion history analysis with Hubble parametrization in Qn gravity

In this paper, we propose a specialized parameterization for the Hubble parameter, inspired by [Formula: see text]CDM cosmology, to investigate the cosmic expansion history of the Universe. This parameterization is employed to analyze the universe’s late-time behavior within the context of [Formula: see text] gravity, where [Formula: see text] represents non-metricity. By using data from 57 Hubble data points, 1048 supernova (SNe) data points, and six Baryon Acoustic Oscillation (BAO) data points, we determine the optimal values for the model parameters. Additionally, we explore three distinct cosmological models based on the parameter [Formula: see text], specifically when it takes on the values of [Formula: see text], [Formula: see text] and [Formula: see text]. The results of our analysis indicate that our proposed parameterization, along with the associated models for different values of [Formula: see text], predicts an accelerated cosmic expansion phase.

Testing the effect of anisotropy on the parametrization of deceleration parameter from recent observational data

In this work, we investigate Bianchi type I universe in the presence of dark energy and dark matter by three parameterizations of deceleration parameter models, which are considered to find solutions of the models. In the framework of an anisotropic cosmology, we constrain the parameters of these models and compared the results with the [Formula: see text]CDM model, by using the datasets from different observational, namely, the Hubble data and type Ia Supernovae Pantheon data. Additionally, the evolution of kinematic cosmographic parameters is investigated. In particular, we analyze the effects of anisotropy on the physical behavior of our mentioned models and compare them with standard [Formula: see text]CDM model.

A Nonparametric Reconstruction of the Hubble Parameter H(z) Based on Radial Basis Function Neural Networks

Accurately measuring the Hubble parameter is vital for understanding the expansion history and properties of the Universe. In this paper, we propose a new method that supplements the covariance between redshift pairs to improve the reconstruction of the Hubble parameter using the observational Hubble data set. Our approach uses a cosmological model-independent radial basis function neural network to effectively describe the Hubble parameter as a function of redshift. Our experiments show that this method results in a reconstructed Hubble parameter of H 0 = 67.1 ± 9.7 km s−1 Mpc−1, which is more noise resistant and fits the ΛCDM model at high redshifts better. Providing the covariance between redshift pairs in subsequent observations will significantly improve the reliability and accuracy of Hubble parametric data reconstruction. Future applications of this method could help overcome the limitations of previous methods and lead to new advances in our understanding of the Universe.

Barrow holographic dark energy in Brane world cosmology

Cosmological features of barrow holographic dark energy (BHDE), a recent generalization of original Holographic dark energy (DE) with a richer structure, are studied in the context of Dvali–Gabadadze–Porrati (DGP) brane, Randall and Sundrum (RS II) brane-world, and the cyclic Universe. It is found that a flat FRW scenario with pressure less dust and a DE component described as BHDE can accommodate late time acceleration with Hubble horizon considered as infrared cut off even in the absence of interaction between the dark sectors. Statefinder diagnostic reveals that these model resemble ΛCDM cosmology in future. It is found that BHDE parameter Δ, despite its theoretically constrained range of values, is significant in describing the evolution of the Universe, however, a classically stable cosmological model cannot be obtained in the RS-II and DGP brane. Viability of the models is also probed with observed Hubble data.

The Star Formation Efficiency during Reionization as Inferred from the Hubble Frontier Fields

A recent ultraviolet luminosity function (UVLF) analysis in the Hubble Frontier Fields, behind foreground lensing clusters, has helped solidify estimates of the faint-end of the z ∼ 5–9 UVLF at up to 5 mag fainter than in the field. These measurements provide valuable information regarding the role of low-luminosity galaxies in reionizing the universe and can help in calibrating expectations for JWST observations. We fit a semiempirical model to the lensed and previous UVLF data from Hubble. This fit constrains the average star formation efficiency (SFE) during reionization, with the lensed UVLF measurements probing halo mass scales as small as M ∼ 2 × 109 M ⊙. The implied trend of SFE with halo mass is broadly consistent with an extrapolation from previous inferences at M ≳ 1010 M ⊙, although the joint data prefer a shallower SFE. This preference, however, is partly subject to systematic uncertainties in the lensed measurements. Near z ∼ 6, we find that the SFE peaks at ∼20% between ∼1011 and 1012 M ⊙. Our best-fit model is consistent with the Planck 2020 determinations of the electron scattering optical depth, and most current reionization history measurements, provided the escape fraction of ionizing photons is f esc ∼ 10%–20%. The joint UVLF accounts for nearly 80% of the ionizing photon budget at z ∼ 8. Finally, we show that recent JWST UVLF estimates at z ≳ 11 require strong departures from the redshift evolution suggested by the Hubble data.

Constraints on the emergent universe from recent temperature and Hubble data

Constraints on the emergent universe from recent temperature and Hubble data

Large exomoons unlikely around Kepler-1625 b and Kepler-1708 b

AbstractThere are more than 200 moons in our Solar System, but their relatively small radii make similarly sized extrasolar moons very hard to detect with current instruments. The best exomoon candidates so far are two nearly Neptune-sized bodies orbiting the Jupiter-sized transiting exoplanets Kepler-1625 b and Kepler-1708 b, but their existence has been contested. Here we reanalyse the Hubble and Kepler data used to identify the two exomoon candidates employing nested sampling and Bayesian inference techniques coupled with a fully automated photodynamical transit model. We find that the evidence for the Kepler-1625 b exomoon candidate comes almost entirely from the shallowness of one transit observed with Hubble. We interpret this as a fitting artefact in which a moon transit is used to compensate for the unconstrained stellar limb darkening. We also find much lower statistical evidence for the exomoon candidate around Kepler-1708 b than previously reported. We suggest that visual evidence of the claimed exomoon transits is corrupted by stellar activity in the Kepler light curve. Our injection-retrieval experiments of simulated transits in the original Kepler data reveal false positive rates of 10.9% and 1.6% for Kepler-1625 b and Kepler-1708 b, respectively. Moreover, genuine transit signals of large exomoons would tend to exhibit much higher Bayesian evidence than these two claims. We conclude that neither Kepler-1625 b nor Kepler-1708 b are likely to be orbited by a large exomoon.

The ALMA-ALPINE [CII] survey: Kennicutt-Schmidt relation in four massive main-sequence galaxies at z ∼ 4.5

Aims. The Kennicutt-Schmidt (KS) relation between the gas and the star formation rate (SFR) surface density (Σgas − ΣSFR) is essential to understand star formation processes in galaxies. To date, it has been measured up to z ∼ 2.5 in main-sequence galaxies. In this Letter our aim is to put constraints at z ∼ 4.5 using a sample of four massive main-sequence galaxies observed by ALMA at high resolution. Methods. We obtained ∼0.3″-resolution [CII] and continuum maps of our objects, which we then converted into gas and obscured SFR surface density maps. In addition, we produced unobscured SFR surface density maps by convolving Hubble ancillary data in the rest-frame UV. We then derived the average ΣSFR in various Σgas bins, and estimated the uncertainties using a Monte Carlo sampling. Results. Our galaxy sample follows the KS relation measured in main-sequence galaxies at lower redshift, and is slightly lower than the predictions from simulations. Our data points probe the high end both in terms of Σgas and ΣSFR, and gas depletion timescales (285–843 Myr) remain similar to z ∼ 2 objects. However, three of our objects are clearly morphologically disturbed, and we could have expected shorter gas depletion timescales (≲100 Myr) similar to merger-driven starbursts at lower redshifts. This suggests that the mechanisms triggering starbursts at high redshift may be different than in the low- and intermediate-z Universe.

Joint Constraints on the Hubble Constant, Spatial Curvature, and Sound Horizon from the Late-time Universe with Cosmography

In this paper, using the latest Pantheon+ sample of Type Ia supernovae, baryon acoustic oscillation measurements, and observational Hubble data, we carry out a joint constraint on the Hubble constant H 0, the spatial curvature ΩK, and the sound horizon at the end of the drag epoch r d. To be model-independent, four cosmography models—i.e., the Taylor series in terms of redshift y 1 = z/(1 + z), , , and the Padé approximants—are used without the assumption of a flat Universe. The results show that H 0 is anticorrelated with ΩK and r d, indicating that smaller ΩK or r d would be helpful in alleviating the Hubble tension. The values of H 0 and r d are consistent with the estimate derived from the Planck cosmic microwave background data based on the flat ΛCDM model, but H 0 is in 2.3 ∼ 3.0σ tension with that obtained by Riess et al. in all these cosmographic approaches. Meanwhile, a flat Universe is preferred by the present observations under all approximations except the third order of y 1 and y 2 of the Taylor series. Furthermore, according to the values of the Bayesian evidence, we found that the flat ΛCDM remains to be the most favored model by the joint data sets, and the Padé approximant of order (2,2), the third order of y 3 and y 1 are the top three cosmographic expansions that fit the data sets best, while the Taylor series in terms of y 2 are essentially ruled out.

Stability of power law cosmological model in f(Q) gravity

In the present study, we have described the accelerated cosmological models of the universe in f( Q) gravity. In f( Q) gravity, the gravitational field equations are modified by a function of the non-metricity tensor, which characterizes the deviation of the affine connection from the metric compatibility condition. We have considered two different forms of f( Q) gravity as f( Q) = β + α Q( n + 1) and f( Q) = β Q + α Q n to explain the dynamics of the expanding universe. We have discussed the dynamics of the universe through graphical representation by considering the power law ( a = kt m ). The free parameters of the models are fitted with the latest observational data set of observational Hubble data, consisting of 57 points, using statistical analysis based on the Markov Chain Monte Carlo method. The best-fit values for the model’s parameter are estimated as H0 = 67.3 ± 1.1, m = 1.0213 ± 0.0071, and k = 65.4 ± 1.1. The parameters of the derived model, like energy density, isotropic pressure, EoS (Equation of state) parameter, and jerk parameter, are discussed. We have described the energy conditions to explain the viability of the considered models. We have also verified the stability of the derived model through perturbation analysis.

Model-independent reconstruction of growth index via Gaussian process

In this paper, the reconstructed growth index is updated by jointed combination from Pantheon+ SNe Ia samples, the observed Hubble data points H(z) at the background level, and redshift space distortion measurements of at the linear perturbation level via Gaussian process. The reconstructed results show that the currently available data points suggest a mild time varying growth index at low redshifts within 3σ regions. No significant deviation from ΛCDM cosmology in GR within 3σ regions was found, while the growth indices for the f(R) and the Dvali–Gabadadze–Porrati gravity are at the boundaries of 3σ regions.