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Strong gravitational lens system catalogues are typically used to constrain a combination of cosmological and empirical power-law lens mass model parameters, often introducing additional empirical parameters and constraints from high resolution imagery. We investigate these lens models using Bayesian methods through a novel alternative that treats...
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... parameter values obtained from MCMC sampling of velocity dispersions obtained using FLRW distances and one of the listed lens models. shown in Table 3 . For the SIS and SPL lens models, the preference is a strong. ...Context 2
... we ver, both FLRW and timescape have a minimum χ 2 per degree of freedom ∼ 2, which shows in both cases the fit could be impro v ed, specifically within the choice and parametrization of the lens model. It is important to note that the Bayes factors of Table 3 should not be interpreted nä ıvely, as lower χ 2 for FLRW models comes at the expense of an unphysical matter density at the extremes M0 0 or M0 1. By contrast, the values of f v0 predicted are within the 2 σ priors f v0 ∈ (0 . 5 , 0 . ...Similar publications
In this paper, cosmic distance duality relation is probed without considering any background cosmological model. The only \textit{a priori} assumption is that the Universe is described by the Friedmann-Lema$\hat{i}$tre-Robertson-Walker (FLRW) metric The strong gravitational lensing (SGL) data is used to construct the dimensionless co-moving distanc...
Citations
We present a new, cosmologically model-independent, statistical analysis of the Pantheon+ type Ia supernovae spectroscopic dataset, improving a standard methodology adopted by Lane et al. We use the Tripp equation for supernova standardisation alone, thereby avoiding any potential correlation in the stretch and colour distributions. We compare the standard homogeneous cosmological model, i.e., CDM, and the timescape cosmology which invokes backreaction of inhomogeneities. Timescape, while statistically homogeneous and isotropic, departs from average Friedmann-Lema\^{\i}tre-Robertson-Walker evolution, and replaces dark energy by kinetic gravitational energy and its gradients, in explaining independent cosmological observations. When considering the entire Pantheon+ sample, we find very strong evidence () in favour of timescape over CDM. Furthermore, even restricting the sample to redshifts beyond any conventional scale of statistical homogeneity, , timescape is preferred over CDM with . These results provide evidence for a need to revisit the foundations of theoretical and observational cosmology.
We present a new, cosmologically model-independent, statistical analysis of the Pantheon+ Type Ia Supernovae spectroscopic data set, improving a standard methodology adopted by Lane et al. We use the Tripp equation for supernova standardization alone, thereby avoiding any potential correlation in the stretch and colour distributions. We compare the standard homogeneous cosmological model, i.e. spatially flat cold dark matter (CDM), and the timescape cosmology which invokes backreaction of inhomogeneities. Timescape, while statistically homogeneous and isotropic, departs from average Friedmann–Lemaître–Robertson–Walker evolution, and replaces dark energy by kinetic gravitational energy and its gradients, in explaining independent cosmological observations. When considering the entire Pantheon+ sample, we find very strong evidence () in favour of timescape over CDM. Furthermore, even restricting the sample to redshifts beyond any conventional scale of statistical homogeneity, , timescape is preferred over CDM with . These results provide evidence for a need to revisit the foundations of theoretical and observational cosmology.
We reanalyse the Pantheon+ supernova catalogue to compare a cosmology with non-FLRW evolution, the timescape cosmology, with the standard ΛCDM cosmology. To this end, we analyse the Pantheon+ for a geometric comparison between the two models. We construct a covariance matrix to be as independent of cosmology as possible, including independence from the FLRW geometry and peculiar velocity with respect to FLRW average evolution. This framework goes far beyond most other definitions of model independence. We introduce new statistics to refine Type Ia supernova (SNe Ia) light-curve analysis. In addition to conventional galaxy correlation functions used to define the scale of statistical homogeneity we introduce empirical statistics which enables refined analysis of the distribution biases of SNe Ia light-curve parameters βc and \alpha {x_{\lower2pt\hbox{\scriptstyle 1}}}. For lower redshifts, the Bayesian analysis highlights important features attributable to the increased number of low-redshift supernovae, the artefacts of model-dependent light-curve fitting and the cosmic structure through which we observe supernovae. This indicates the need for cosmology-independent data reduction to conduct a stronger investigation of the emergence of statistical homogeneity and to compare alternative cosmologies in light of recent challenges to the standard model. Dark energy is generally invoked as a place-holder for new physics. For the first time, we find evidence that the timescape cosmology may provide a better overall fit than ΛCDM and that its phenomenology may help disentangle other astrophysical puzzles. Our from-first-principles reanalysis of Pantheon+ supports future deeper studies between the interplay of matter and nonlinear spacetime geometry in a data-driven setting.
