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Related papers: The function q(z) as a consistency check for cosmo…

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Redshift drift refers to the phenomena that redshift of cosmic objects is a function of time. Measurement of redshift drift is of fundamental importance in physical cosmology and can be utilized to distinguish different cosmological models.…

General Relativity and Quantum Cosmology · Physics 2020-06-16 Snehasish Bhattacharjee , P. K. Sahoo

We consider a nonrelativistic cosmological model introduced in [1] and derived as the nonrelativistic limit (or approximation at sub-Hubble scales) of a general relativistic model in [3, 4]. The latter is defined by an energy-momentum…

General Physics · Physics 2017-12-11 Peter C. Stichel

We suggest a crucial direct-observational test for measuring distinction between the standard $\Lambda$CDM model and recently proposed phantom dark energy positive curvature cosmological model. The test is based on the fundamental…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-20 S. I. Shirokov , Yu. V. Baryshev

Proceeding from a homogeneous and isotropic Friedmann universe a conceptional problem concerning light propagation in an expanding universe is brought up. As a possible solution of this problem it is suggested that light waves do not scale…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Peter Huber

In this work, the cosmic solutions, particularly the well-known $\Lambda$CDM model, are investigated in the framework of the Gauss-Bonnet gravity, where the gravitational action incorporates the Gauss-Bonnet invariant function. We utilize a…

General Relativity and Quantum Cosmology · Physics 2024-09-26 N. Myrzakulov , Anirudh Pradhan , Archana Dixit , S. H. Shekh

Cosmologists are exploring two possible sets of explanations for the remarkable observation of cosmic acceleration: dark energy fills space or general relativity fails on cosmological scales. We define a null test parameter $\epsilon(k,a)…

Astrophysics · Physics 2008-11-26 Viviana Acquaviva , Amir Hajian , David N. Spergel , Sudeep Das

One of the most significant discoveries in modern cosmology is that the universe is currently in a phase of accelerated expansion after a switch from a decelerated expansion. The redshift corresponding to this epoch is referred to as the…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-18 Darshan Kumar , Deepak Jain , Shobhit Mahajan , Amitabha Mukherjee , Akshay Rana

A general formula for the correlation function in redshift space is derived in linear theory. The formula simultaneously includes wide-angle effects and cosmological distortions. The formula is applicable to any pair with arbitrary angle…

Astrophysics · Physics 2009-10-31 Takahiko Matsubara

This work investigates the dynamical evolution of the universe within the framework of symmetric teleparallel $f(Q,\mathcal{T})$ gravity, where $Q$ is the non-metricity scalar and $\mathcal{T}$ is the trace of the energy-momentum tensor. We…

General Relativity and Quantum Cosmology · Physics 2026-05-19 S. H. Shekh , S. B. Thool , Pankaj Kumar , P. C. Kalan , R. M. Dhaigude

The use of Gaussian Processes with a measurement of the cosmic expansion rate based solely on the observation of cosmic chronometers provides a completely cosmology-independent reconstruction of the Hubble constant H(z) suitable for testing…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-21 Fulvio Melia , Manoj K. Yennapureddy

We investigate the evolution of the cosmic star formation rate density (SFRD) from redshift z=20 to z=0 and compare it with the observational one by Madau and Dickinson derived from recent compilations of UV and IR data. The theoretical…

The clustering of galaxies observed in future redshift surveys will provide a wealth of cosmological information. Matching the signal at different redshifts constrains the dark energy driving the acceleration of the expansion of the…

Observational evidence consistently shows that the universe is spatially flat and undergoes Lorentzian time dilation as a function of redshift. In combination, such discoveries suggest that a Minkowskian description of cosmology might be…

General Physics · Physics 2024-10-14 Artur Novais , A. L. B. Ribeiro

We investigate the evolution of cosmic structures within the framework of modified gravity, specifically focusing on theories described by the function $f(R, L_m)$, where $R$ is the Ricci scalar and $L_m$ is the matter Lagrangian. This…

General Relativity and Quantum Cosmology · Physics 2025-07-08 G. K. Goswami , J. P. Saini

The cosmographic expansion history of the universe is investigated by using the 557 type Ia supernovae from the Union2 Compilation set along with the current estimates involving the product of the CMB acoustic scale $\ell_{A}$ and the BAO…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 B. Santos , J. C. Carvalho , J. S. Alcaniz

Recently, Cai and Su [Phys. Rev. D {\bf 81}, 103514 (2010)] found that the sign of interaction $Q$ in the dark sector changed in the approximate redshift range of $0.45\,\lsim\, z\,\lsim\, 0.9$, by using a model-independent method to deal…

General Relativity and Quantum Cosmology · Physics 2011-11-22 Hao Wei

Recent measurements of the parameters of the Concordance Cosmology Model ($\Lambda$CDM) done in the low-redshift Universe with Supernovae Ia/Cepheids, and in the distant Universe done with Cosmic Microwave Background (CMB) imply different…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-26 B. Czerny , M. L. Martínez-Aldama , G. Wojtkowska , M. Zajaček , P. Marziani , D. Dultzin , M. H. Naddaf , S. Panda , R. Prince , R. Przyluski , M. Ralowski , M. Śniegowska

We examine a modified teleparallel gravity model defined by $f(T,T_{G})=T+\gamma\sqrt{T_{G}}+\delta\sqrt{T}$ by introducing an exponential $Om(z)$ diagnostic of the form $Om(z)=\alpha e^{\frac{z}{1+z}}+\beta$. This novel form captures…

General Relativity and Quantum Cosmology · Physics 2025-06-10 Amit Samaddar , S. Surendra Singh

We develop a methodology to use the redshift dependence of the galaxy 2-point correlation function (2pCF) across the line-of-sight, $\xi(r_{\bot})$, as a probe of cosmological parameters. The positions of galaxies in comoving Cartesian…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-02 Xiao-Dong Li , Changbom Park , Cristiano G. Sabiu , Hyunbae Park , Cheng Cheng , Juhan Kim , Sungwook E. Hong

The variation of the expansion rate of the Universe with time produces an evolution in the cosmological redshift of distant sources (for example quasar Lyman-$\alpha$ absorption lines), that might be directly observed by future ultra…

Astrophysics · Physics 2009-11-13 A. Balbi , C. Quercellini