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In this work, we study the extended viscous dark energy models in the context of matter perturbations. To do this, we assume an alternative interpretation of the flat Friedmann-Lema\^itre-Robertson-Walker Universe, through the nonadditive…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-13 W. J. C. da Silva , R. Silva

We apply two methods, namely the Gaussian processes and the non-parametric smoothing procedure, to reconstruct the Hubble parameter $H(z)$ as a function of redshift from 15 measurements of the expansion rate obtained from age estimates of…

Cosmology and Nongalactic Astrophysics · Physics 2016-03-02 Zhengxiang Li , J. E. Gonzalez , Hongwei Yu , Zong-Hong Zhu , J. S. Alcaniz

I investigate the consistency of the VIMOS Public Extragalactic Redshift Survey v7 galaxy sample with the expansion history and linear growth rate predicted by General Relativity (GR) and a Planck (2015) cosmology. To do so, I measure the…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-27 Michael J. Wilson

We investigate the null tests of cosmic accelerated expansion by using the Baryon Acoustic Oscillation (BAO) data measured by the Dark Energy Spectroscopic Instrument (DESI) and reconstruct the dimensionless Hubble parameter $E(z)$ from the…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-23 Xuchen Lu , Shengqing Gao , Yungui Gong

Measurements of the cosmological parameter $S_8$ provided by cosmic microwave background and large scale structure data reveal some tension between them, suggesting that the clustering features of matter in these early and late cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-08 Felipe Avila , Armando Bernui , Alexander Bonilla , Rafael C. Nunes

Constraints on the main cosmological parameters using CMB or large scale structure data are usually based on power-law assumption of the primordial power spectrum (PPS). However, in the absence of a preferred model for the early universe,…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-14 Dhiraj Kumar Hazra , Arman Shafieloo , Tarun Souradeep

This paper examines the late-time accelerating Universe and the formation of large-scale structures within the modified symmetric teleparallel gravity framework, specifically using the $f(Q)$-gravity model, in light of recent cosmological…

General Relativity and Quantum Cosmology · Physics 2024-12-31 Shambel Sahlu , Amare Abebe

In this work, we implement Gaussian process regression to reconstruct the expansion history of the universe in a model-agnostic manner, using the Pantheon-Plus SN-Ia compilation in combination with two different BAO measurements (SDSS-IV…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-02 Purba Mukherjee , Anjan Ananda Sen

In the present investigation we use observational data of $ f \sigma_ {8} $ to determine observational constraints in the plane $(\Omega_{m0},\sigma_{8})$ using two different methods: the growth factor parametrization and the numerical…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-03 A. M. Velásquez-Toribio , Júlio C. Fabris

Perhaps the most explored hypothesis for the accelerated cosmic expansion rate arises in the context of extra fields or modifications to General Relativity. A prevalent approach is to parameterize the expansion history through the equation…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-14 Mariana Jaber , Gustavo Arciniega , Luisa G. Jaime , Omar A. Rodríguez-López

We propose and construct a two-parameter perturbative expansion around a Friedmann-Lema\^{i}tre-Robertson-Walker geometry that can be used to model high-order gravitational effects in the presence of non-linear structure. This framework…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-15 Sophia R. Goldberg , Timothy Clifton , Karim A. Malik

The recent extension of the Hubble diagram of Supernovae and quasars to redshifts much higher than 1 prompted a revived interest in non-parametric approaches to test cosmological models and to measure the expansion rate of the Universe. In…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-27 Lorenzo Giambagli , Duccio Fanelli , Guido Risaliti , Matilde Signorini

We present and test a new method for the reconstruction of cosmological initial conditions from a full-sky galaxy catalogue. This method, called ZTRACE, is based on a self-consistent solution of the growing mode of gravitational…

Astrophysics · Physics 2009-10-31 P. Monaco , G. Efstathiou

Modified gravity models with scale-dependent linear growth typically exhibit an enhancement in the power spectrum beyond a certain scale. The conventional methods for extracting cosmological information usually involve inferring modified…

This review summarizes recent attempts to reconstruct the expansion history of the Universe and to probe the nature of dark energy. Reconstruction methods can be broadly classified into parametric and non-parametric approaches. It is…

Astrophysics · Physics 2008-11-26 Varun Sahni , Alexei Starobinsky

The prospect of nonparametric reconstructions of cosmological parameters from observational data sets has been a popular topic in the literature for a number of years. This has mainly taken the form of a technique based on Gaussian…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-24 Konstantinos Dialektopoulos , Jackson Levi Said , Jurgen Mifsud , Joseph Sultana , Kristian Zarb Adami

We make use of the perturbation theory for modified gravity models that we developed in previous works and apply it to construct the fullshape galaxy power spectrum for the Symmetron modified gravity model. First, we study the growth rate,…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-27 Gerardo Morales-Navarrete , Jorge L. Cervantes-Cota

In this paper, we propose to estimate the spatial curvature of the universe and the cosmic opacity in a model-independent way with expansion rate measurements, $H(z)$, and type Ia supernova (SNe Ia). On the one hand, using a nonparametric…

Cosmology and Nongalactic Astrophysics · Physics 2017-10-04 Guo-Jian Wang , Jun-Jie Wei , Zheng-Xiang Li , Jun-Qing Xia , Zong-Hong Zhu

Nonlocal massive gravity can provide an interesting explanation for the late-time cosmic acceleration, with a dark energy equation of state $w_{\rm DE}$ smaller than $-1$ in the past. We derive the equations of linear cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-11 Savvas Nesseris , Shinji Tsujikawa

Analyses of cosmic shear typically condense weak lensing information over a range of scales to a single cosmological parameter, $S_8$. This paper presents a method to extract more information from Stage-IV cosmic shear measurements by…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-30 Calvin Preston , Alexandra Amon , George Efstathiou