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Bayesian statistics and Markov Chain Monte Carlo (MCMC) algorithms have found their place in the field of Cosmology. They have become important mathematical and numerical tools, especially in parameter estimation and model comparison. In…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-02 Luis E. Padilla , Luis O. Tellez , Luis A. Escamilla , J. Alberto Vazquez

In this paper, a parametrization describing the kinematical state of the universe via cosmographic approach is considered, where the minimum input is the assumption of the cosmological principle, i.e. the Friedmann-Robertson-Walker metric.…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Lixin Xu , Yuting Wang

We introduce new CosmoEJS modules to improve the investigation of the consequences of constraints on the parameter values of cosmological models. We use CosmoMC to fit dark energy models and modified gravity models to recent data from the…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-14 Jacob Moldenhauer , Francis Cavanna , William O'toole , William Zimmerman

The field equations of modified gravity theories, when considering a homogeneous and isotropic cosmological model, always become autonomous differential equations. This relies on the fact that in such models all variables only depend on…

General Relativity and Quantum Cosmology · Physics 2023-02-03 Christian G. Boehmer , Erik Jensko , Ruth Lazkoz

We present a novel dynamical dark energy model within the frameworks of both Einstein gravity and Horava-Lifshitz gravity. Utilizing CDMMA parametrization of the dark energy equation of state $\omega(z)$, we derive solutions to the field…

General Relativity and Quantum Cosmology · Physics 2024-11-26 Ujjal Debnath , Himanshu Chaudhary , Niyaz Uddin Molla , S. K. J. Pacif , G. Mustafa

We explore cosmological perturbations in a modified Gauss-Bonnet f(G) gravity, using a 1+3 covariant formalism. In such a formalism, we define gradient variables to get perturbed linear evolution equations. We transform these linear…

General Relativity and Quantum Cosmology · Physics 2022-09-20 Albert Munyeshyaka , Joseph Ntahompagaze , Tom Mutabazi

In the current work, we have implemented an extension of the standard Gaussian Process formalism, namely the Multi-Task Gaussian Process with the ability to perform a joint learning of several cosmological data simultaneously. We have…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-15 Balakrishna S. Haridasu , Vladimir V. Luković , Michele Moresco , Nicola Vittorio

We present two new diagnostics based on the intrinsic shape alignments of group/cluster size dark matter halos to disentangle the effect of $f(R)$ gravity from that of massive neutrinos. Using the snapshot data from a series of the {\small…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-09 Jounghun Lee , Suho Ryu , Marco Baldi

In the gravitational-wave analysis of pulsar-timing-array datasets, parameter estimation is usually performed using Markov Chain Monte Carlo methods to explore posterior probability densities. We introduce an alternative procedure that…

General Relativity and Quantum Cosmology · Physics 2024-05-16 Michele Vallisneri , Marco Crisostomi , Aaron D. Johnson , Patrick M. Meyers

We present a thorough analysis of the cosmological perturbations in Generalised Massive Gravity. This is an extension of de Rham-Gabadadze-Tolley theory where the translation invariance in the St\"uckelberg field space is broken. This…

High Energy Physics - Theory · Physics 2020-04-15 Michael Kenna-Allison , A. Emir Gumrukcuoglu , Kazuya Koyama

We apply a new model for the spherically averaged correlation function at large pair separations to the measurement of the clustering of luminous red galaxies (LRGs) made from the SDSS by Cabre and Gaztanaga(2009). Our model takes into…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Ariel G. Sanchez , M. Crocce , A. Cabre , C. M. Baugh , E. Gaztanaga

We review observational tests for the homogeneity of the Universe on large scales. Redshift and peculiar velocity surveys, radio sources, the X-Ray Background, the Lyman-$\alpha$ forest and the Cosmic Microwave Background are used to set…

Astrophysics · Physics 2007-05-23 Ofer Lahav

We explore the cosmological implications of generalized entropic models within the framework of Gravity-Thermodynamics (GT) approaches. These models, characterized by three or four additional free parameters, are designed to capture…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-06 Udit K. Tyagi , Sandeep Haridasu , Soumen Basak

Cosmological constraints of Modified Gravity (MG) models are seldom carried out rigorously. First, even though general MG models evolve differently (i.e., background and perturbations) to the standard cosmological model, it is usual to…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-27 Wilmar Cardona , Rubén Arjona , Alejandro Estrada , Savvas Nesseris

In this manuscript, we investigate the constraints on dynamical vacuum models within the framework of $\Lambda(t)$CDM cosmology by assuming a parameterization of the vacuum energy density as $\rho_{\Lambda}(t)=\rho_{\Lambda 0} \left[1 +…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-14 Yerlan Myrzakulov , M. Koussour , M. Bulanbay , S. Muminov , J. Rayimbaev

As the statistical power of imaging surveys grows, it is crucial to account for all systematic uncertainties. This is normally done by constructing a model of these uncertainties and then marginalizing over the additional model parameters.…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-03 Jaime Ruiz-Zapatero , Boryana Hadzhiyska , David Alonso , Pedro G. Ferreira , Carlos García-García , Arrykrishna Mootoovaloo

This paper is the third in a series on submillimeter galaxy magnification bias, focusing on the tomographic scenario. It refines the methodology used to constrain the halo occupation distribution model and cosmological parameters within a…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-12 L. Bonavera , M. M. Cueli , J. González-Nuevo , J. M. Casas , D. Crespo

We study the statefinder parameters of a cosmological model based on scale-dependent gravity. The effective Einstein field equations come from an average effective action. From the dynamical system, we derive analytical expressions that…

General Relativity and Quantum Cosmology · Physics 2022-05-12 Pedro D. Alvarez , Benjamin Koch , Cristobal Laporte , Felipe Canales , Angel Rincon

We propose a method based on the redshift dependence of the Alcock-Paczynski (AP) test to measure the expansion history of the Universe. It uses the isotropy of the galaxy density gradient field to constrain cosmological parameters. If the…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-30 Xiao-Dong Li , Changbom Park , Jaime E. Forero-Romero , Juhan Kim

Cosmological weak lensing by the large scale structure of the Universe, cosmic shear, is coming of age as a powerful probe of the parameters describing the cosmological model and matter power spectrum. It complements CMB studies, by…

Astrophysics · Physics 2009-11-10 Patrick Simon , Lindsay J. King , Peter Schneider