Cosmological Parameter Inference with Bayesian Statistics

Padilla, Luis E.; Tellez, Luis O.; Escamilla, Luis A.; Vázquez, J. Alberto

doi:10.3390/universe7070213

Cited by 31 publications

(9 citation statements)

References 128 publications

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“…See Ref. [145], and references therein, for an extended review of the cosmological parameter inference and model selection procedure. We obtain the observational constraints on all the parameters of the models-Λ s CDM, Λ s CDM+z † = 2.32 (a particular case of Λ s CDM), and ΛCDM (for comparison purposes)-by using first only Table I.…”

Section: Observational Constraints and Resultsmentioning

confidence: 99%

Relaxing cosmological tensions with a sign switching cosmological constant

Akarsu,

Kumar,

Ozulker

et al. 2021

Preprint

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Inspired by the recent conjecture that the universe has transitioned from AdS vacua to dS vacua in the late universe made via graduated dark energy, we extend the standard ΛCDM model by a cosmological 'constant' (Λs) that switches sign at certain redshift, z † , and name it as ΛsCDM. We discuss in detail the construction and theoretical features of this model, and find out that, when the consistency of the ΛsCDM model with the cosmic microwave background (CMB) data is ensured, (i) z † 1.1 is implied by the condition that the universe monotonically expands, (ii) H0 is inversely correlated with z † and reaches ≈ 74.5 km s −1 Mpc −1 for z † = 1.5, (iii) H(z) presents an excellent fit to the Ly-α measurements provided that z † 2.34. We further investigate the model constraints by using the full Planck CMB data, with and without baryon acoustic oscillations (BAO) data. We find that the CMB data alone does not constrain z † but CMB+BAO dataset favors the sign switch of Λs providing the constraint: z † = 2.44 ± 0.29 (68% CL). Our analysis reveals that the lower and upper limits of z † are controlled by the Galaxy and Ly-α BAO measurements, respectively, and the larger z † values imposed by the Galaxy BAO data prevent the model from achieving the highest local H0 measurements. In general, the ΛsCDM model (i) relaxes the so-called H0 tension while being fully consistent with the TRGB measurement, (ii) removes the discrepancy with the Ly-α measurements, (iii) relaxes the so-called S8 tension, and (iv) finds a better agreement with the BBN constraints of physical baryon density. We find no strong statistical evidence to discriminate between the ΛsCDM and ΛCDM models. However, interesting and promising features of the ΛsCDM model, as turned out in our study, provide an upper edge over ΛCDM.

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Section: Observational Constraints and Resultsmentioning

confidence: 99%

Relaxing cosmological tensions with a sign switching cosmological constant

Akarsu,

Kumar,

Ozulker

et al. 2021

Preprint

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“…See Ref. [74], and references therein, for an extended review of the cosmological parameter inference and model selection procedure.…”

Section: Models and Priorsmentioning

confidence: 99%

Model selection applied to non-parametric reconstructions of the Dark Energy

Escamilla¹,

Vazquez²

2021

Preprint

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The main aim of this paper is to perform a model comparison for non-parametric reconstructions of the key properties that describe the dark energy of the Universe i.e. energy density and the equation of state (EoS). We carry out this process by using a binning and a linear interpolation methodologies, and on the top of that, we incorporate a correlation function mechanism. An extension of the two of them was also introduced, where internal amplitudes are allowed to vary in height as well as in position. The reconstructions were made with data from the Hubble parameter, Supernovae Type Ia and Baryon Acoustic Oscillations (H+SN+BAO), all of which span a range from z = 0.01 to z = 2.8. First we perform the parameter estimation for each of the reconstructions to then provide a model selection through the Bayesian Evidence. Throughout our process we found a better fit to the data, up to 4σ compared to ΛCDM, and the presence of some interesting features, i.e. an oscillatory behaviour at late times, a decrease in the dark energy density component at early times and a transition to the phantom divide-line in the EoS. To discern these features from noisy contributions, we include a principal component analysis and found that some of these characteristics should be taken into account to satisfy observations.

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“…The results are shown in Table I. Following the Jeffreys guideline [57], if ln B i,j > 5 we have a decisive strength against model i; if 5 > ln B i,j > 2.5 it means a strong strength; if 2.5 > ln B i,j > 1 we have a significant strength and if ln B i,j < 1 the data prefers model i. In general, we should be careful taking the values of the Bayes factor since some of the parameters were unconstrained by the data.…”

Section: Cosmological Constraintsmentioning

confidence: 99%

“…As mentioned in[49], the process of inferring the MPS is model-dependent, therefore we will consider the constraints obtained here as an approximation.3 See[57] for a bayesian inference review.…”

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confidence: 99%

Cosmological constraints on the Multi Scalar Field Dark Matter model

Téllez-Tovar¹,

Matos²,

Vázquez³

2021

Preprint

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The main aim of this paper is to provide cosmological constraints on the Multi Scalar Field Dark Matter model (MSFDM), in which we assume the dark matter is made up of different ultra-light scalar fields. As a first approximation, we consider they are real and do not interact with each other. We study the equations for both the background and perturbations for N -fields and present the evolution of the density parameters, the mass power spectrum and the CMB spectrum. In particular, we focus on two scalar fields with several combinations for the potentials, however the work, along with the code, can be easily extended to more fields. We use the data from BAO, Big Bang Nucleosynthesis, Lyman-α forest and Supernovae to find constraints on the sampling parameters for the cases of a single field and double field, along with the Bayesian evidence. We found that some combinations of the potentials get penalized through the evidence, however for others there is a preference as good as for the cold dark matter.

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Cosmological Parameter Inference with Bayesian Statistics

Cited by 31 publications

References 128 publications

Relaxing cosmological tensions with a sign switching cosmological constant

Relaxing cosmological tensions with a sign switching cosmological constant

Model selection applied to non-parametric reconstructions of the Dark Energy

Cosmological constraints on the Multi Scalar Field Dark Matter model

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