English
Related papers

Related papers: Null test for cosmic curvature using Gaussian proc…

200 papers

We use the newly published 28 observational Hubble parameter data ($H(z)$) and current largest SNe Ia samples (Union2.1) to test whether the universe is transparent. Three cosmological-model-independent methods (nearby SNe Ia method,…

Cosmology and Nongalactic Astrophysics · Physics 2013-01-15 Kai Liao , Zhengxiang Li , Jing Ming , Zong-Hong Zhu

We use the state-of-the-art data on cosmic chronometers (CCH) and the Pantheon+ compilation of supernovae of Type Ia (SNIa) to test the constancy of the SNIa absolute magnitude, $M$, and the robustness of the cosmological principle (CP) at…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-07 Arianna Favale , Adrià Gómez-Valent , Marina Migliaccio

The Cosmic Microwave Background (CMB) anisotropy constrains the geometry of the Universe because the positions of the acoustic peaks of the angular power spectrum depend strongly on the curvature of underlying three-dimensional space. In…

Astrophysics · Physics 2009-11-13 J. Dunkley , M. Bucher , P. G. Ferreira , K. Moodley , C. Skordis

In the context of the Fab-Four theory of gravity in a Friedmann-Lema\^itre-Robertson-Walker background, in this work we use the cosmography approach to study a particular self-tuning filter solution focused on a zero-curvature fixed point…

General Relativity and Quantum Cosmology · Physics 2023-06-29 Celia Escamilla-Rivera , José María de Albornoz-Caratozzolo , Sebastián Nájera

Assuming that the background geometry is filled with free gas consisting of matter and radiation and no phase transitions being occurred in the early Universe, we discuss the thermodynamics of this {\it closed} system using classical…

General Relativity and Quantum Cosmology · Physics 2015-05-30 A. Tawfik , H. Magdy

As evidenced by a great number of works, it is common practice to assume that the Universe is flat. However, the majority of studies which make use of observational data to constrain the curvature density parameter are premised on the…

General Relativity and Quantum Cosmology · Physics 2019-07-18 Christine R. Farrugia , Joseph Sultana

The $H_0$-tension problem poses a confrontation of dark energy driving late-time cosmological expansion measured by the Hubble parameter $H(z)$ over an extended range of redshifts $z$. Distinct values $H_0\simeq 73$ km\,s$^{-1}$Mpc$^{-1}$…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-15 Maurice H. P. M. van Putten

We use current measurements of the expansion rate $H(z)$ and cosmic background radiation bounds on the spatial curvature of the Universe to impose cosmological model-independent constraints on cosmic opacity. To perform our analyses, we…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 R. F. L. Holanda , J. C. Carvalho , J. S. Alcaniz

The Hubble constant ($H_0$), which represents the expansion rate of the Universe, is one of the most important cosmological parameters. The recent measurements of $H_0$ using the distance ladder methods such as Type Ia Supernovae (SNe Ia)…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-14 Rahul Kumar Thakur , Shashikant Gupta , Rahul Nigam , PK Thiruvikraman

We present a fitting formula for the luminosity and angular diameter distances in cosmological models with pressureless matter, a cosmological constant and zero spatial curvature. The formula has a relative error of less than 0.4% for…

Astrophysics · Physics 2011-05-23 Ue-Li Pen

The spatial curvature ($\Omega_K$) of the Universe is one of the most fundamental quantities that could give a link to the early universe physics. In this paper we develop an approximate method to compute the nonlinear matter power…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-19 Ryo Terasawa , Ryuichi Takahashi , Takahiro Nishimichi , Masahiro Takada

The $f(Q,T)$ cosmological model has emerged as a promising framework for understanding various aspects of cosmic evolution. In this study, we focused on obtaining the constraints of the free parameters in the non-linear form of…

General Relativity and Quantum Cosmology · Physics 2024-03-21 Rahul Bhagat , S. A. Narawade , B. Mishra , S. K. Tripathy

We have probed a cosmological model in $f(R)$-gravity, which is a cubic equation in scalar curvature $R$. The terms arise due to nonlinear $f(R)$ function are treated as energy due to curvature inspired geometry. As a result, we find…

General Relativity and Quantum Cosmology · Physics 2023-05-03 G. K. Goswami , Rita Rani , Harshna Balhara , J. K. Singh

The Universe could be spatially flat, positively curved or negatively curved. Each option has been popular at various times, partly affected by an understanding that models tend to evolve away from flatness. The curvature of the Universe is…

Astrophysics · Physics 2009-08-18 Elena Pierpaoli , Douglas Scott , Martin White

Recent observational analyses have suggested possible evidence of hemisphere asymmetry in cosmological datasets. Parameterizations of this kind place observers in a privileged position-specifically on the plane that divides the two…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-16 Xin Wang , Zhiqi Huang

We present explicit expressions for the calculation of cosmological look back time, for zero cosmological constant and arbitrary density parameter $\Omega$, which, in the limit as redshift becomes infinite, give the age of the universe. The…

Astrophysics · Physics 2007-05-23 Kevin Krisciunas

The tension between the Hubble constant obtained from the local measurements and from cosmic microwave background (CMB) measurements motivated us to consider the cosmological model beyond $\Lambda$CDM one. We investigate the cosmology in…

General Relativity and Quantum Cosmology · Physics 2022-06-15 Jing Li , Yongxiang Zhou , Xun Xue

We propose an improved method to determine the sound horizon in a cosmological model-independent way by using the latest observations of BAO measurements from DES, BOSS/eBOSS, and DESI surveys and gravitationally time-delay lensed quasars…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-16 Tonghua Liu , Shuo Cao , Jieci Wang

A recently published paper by Nielsen, Guffanti and Sarkar argues that the evidence for cosmic acceleration is marginal and that a coasting universe - the Milne Universe - fits the same supernovae data in a Hubble diagram nearly as well.…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-31 H. I. Ringermacher , L. R. Mead

We use a cosmology-independent method to calibrate gamma-ray burst (GRB) from the observational Hubble data (OHD) with the cosmic chronometers method. By using Gaussian Process to reconstruct OHD, we calibrate the Amati relation ($E_{\rm…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-03 Zihao Li , Bin Zhang , Nan Liang