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For different gravitational models we consider limitations on their parameters coming from recent observational data for type Ia supernovae, baryon acoustic oscillations, and from 34 data points for the Hubble parameter $H(z)$ depending on…

General Relativity and Quantum Cosmology · Physics 2014-11-06 G. S. Sharov , E. G. Vorontsova

Accurately measuring the Hubble parameter is vital for understanding the expansion history and properties of the universe. In this paper, we propose a new method that supplements the covariance between redshift pairs to improve the…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-23 Jian-Chen Zhang , Yu Hu , Kang Jiao , Hong-Feng Wang , Yuan-Bo Xie , Bo Yu , Li-Li Zhao , Tong-Jie Zhang

The $\Lambda$ cold dark matter ($\Lambda\textrm{CDM}$) model is currently known as the simplest cosmology model that best describes observations with minimal number of parameters. Here we introduce a cosmology model that is preferred over…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-05 Chan-Gyung Park

We constrain two non-flat time-evolving dark energy cosmological models by using Hubble parameter data, Type Ia supernova apparent magnitude measurements, and baryonic acoustic oscillation peak length scale observations. The inclusion of…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-22 Omer Farooq , Data Mania , Bharat Ratra

The Hubble constant ($H_0$) is one of the most important parameters in the standard $\rm \Lambda CDM$ model. The measurements given by the main two methods show a gap larger than $4\sigma$, which is known as Hubble tension. Fast radio…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-18 D. H. Gao , Q. Wu , J. P. Hu , S. X. Yi , X. Zhou , F. Y. Wang , Z. G. Dai

The $\Lambda$CDM model successfully explains the majority of cosmological observations. However, the $\Lambda$CDM model is challenged by Hubble tension, a remarkable difference of Hubble constant $H_0$ between measurements from local probe…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-18 Q. Wu , G. Q. Zhang , F. Y. Wang

For precision cosmological studies it is important to know the local properties of the reference point from which we observe the Universe. Particularly for the determination of the Hubble constant with low-redshift distance indicators, the…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-25 Hans Boehringer , Gayoung Chon , Chris A. Collins

We measure cosmological parameters using the three-dimensional power spectrum P(k) from over 200,000 galaxies in the Sloan Digital Sky Survey (SDSS) in combination with WMAP and other data. Our results are consistent with a ``vanilla'' flat…

Measurements of the Hubble constant, $H_0$, from the cosmic distance ladder are currently in tension with the value inferred from Planck observations of the CMB and other high redshift datasets if a flat $\Lambda$CDM cosmological model is…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-18 Eric J. Baxter , Blake D. Sherwin

We parameterize the Hubble function by adding Hermitian wavelets to the Hubble radius of $\Lambda$CDM. This allows us to build Hubble functions that oscillate around $\Lambda$CDM at late times without modifying its angular diameter distance…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-05 Luis A. Escamilla , Emre Özülker , Özgür Akarsu , Eleonora Di Valentino , J. A. Vázquez

We examine the dark energy and matter densities allowed by precision measurements of distances out to various redshifts, in the presence of spatial curvature and (near) arbitrary behavior of the dark energy equation of state. Degeneracies…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-22 Arman Shafieloo , Eric V. Linder

A plethora of observational data obtained over the last couple of decades has allowed cosmology to enter into a precision era and has led to the foundation of the standard cosmological constant and cold dark matter paradigm, known as the…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-31 Rubén Arjona , Savvas Nesseris

In this paper, we discuss a model-independent way to obtain the present dark matter density parameter ($\Omega_{\rm{c,0}}$) by combining gas mass fraction measurements in galaxy clusters ($f_{gas}$), type Ia supernovae (SNe Ia) observations…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-04 R. F. L. Holanda , R. S. Gonçalves , J. E. Gonzales , J. S. Alcaniz

The redshift of all cosmological sources drifts by a systematic velocity of order a few m/s over a century due to the deceleration of the Universe. The specific functional dependence of the predicted velocity shift on the source redshift…

Astrophysics · Physics 2011-02-11 Abraham Loeb

We present an extensive comparison of models of structure formation with observations, based on linear and quasi-linear theory. We assume a critical matter density, and study both cold dark matter models and cold plus hot dark matter…

Astrophysics · Physics 2015-06-24 Andrew R Liddle , David H Lyth , R K Schaefer , Q Shafi , Pedro T P Viana

The cosmographic approach is gaining considerable interest as a model-independent technique able to describe the late expansion of the universe. Indeed, given only the observational assumption of the cosmological principle, it allows to…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-11 Micol Benetti , Salvatore Capozziello

We propose a model-independent way to determine the cosmic curvature using the Hubble parameter $H(z)$ measured with cosmic chronometers and the comoving distance $D(z)$ inferred from HII galaxies. We employ Gaussian processes to smooth the…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-18 Jing Zheng , Fulvio Melia , Tong-Jie Zhang

In this paper, we go further and propose a cosmological model-independent approach to simultaneously determine the Hubble constant and cosmic curvature with strong lensing time-delay measurements, without any prior assumptions regarding the…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-19 Tonghua Liu , Shuo Cao , Sixuan Zhang , Chenfa Zheng , Wuzheng Guo

We build a simple cosmological model by means of a parabolic Lema\^{i}tre-Tolman-Bondi (LTB) metric up to a redshift $z\simeq 0.4$, an hyperbolic Friedmann metric for $z\sim 0.4$ up to the scale where dimming galaxies are observed ($z\sim…

General Relativity and Quantum Cosmology · Physics 2009-07-06 Stefano Viaggiu
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