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We study the constraints which the next generation of radio telescopes could place on the nature of dark energy, dark matter and inflation by studying the gravitational lensing of high redshift 21 cm emission, and we compare with the…

Astrophysics · Physics 2009-06-23 R. Benton Metcalf , S. D. M. White

Determining the spatial curvature $\Omega_K$ of the Universe has long been crucial in cosmology. In practice, this effort is often entangled with assumptions of dark energy. A combination of distance ($D_{\rm M}$, $D_{\rm L}$) and expansion…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-30 Zhennan Li , Pengjie Zhang

Cosmic microwave background (CMB) anisotropy (spatial inhomogeneity) data provide the tightest constraints on the Hubble constant, matter density, spatial curvature, and dark energy dynamics. Other data, sensitive to the evolution of only…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-04 Chan-Gyung Park , Bharat Ratra

Joint analysis of Cosmic Microwave Background, Baryon Acoustic Oscillation, and supernova data has enabled precision estimation of cosmological parameters. New programs will push to 1% uncertainty in the dark energy equation of state and…

Cosmology and Nongalactic Astrophysics · Physics 2009-02-26 Lincoln Greenhill , Elizabeth Humphreys , Wayne Hu , Lucas Macri , David Murphy , Karen Masters , Yoshiaki Hagiwara , Hideyuki Kobayashi , Yasuhiro Murata

Scalar fields aptly describe equation of state of dark energy. The scalar field models were initially proposed to circumvent the fine tuning problem of cosmological constant. However, the model parameters also need a fine tuning of their…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-19 Archana Sangwan , Ashutosh Tripathi , H. K. Jassal

We examine flat models containing a dark matter component and an arbitrary dark energy component, subject only to the constraint that the dark energy satisfies the weak energy condition. We determine the constraints that these conditions…

Astrophysics · Physics 2008-11-26 A. A. Sen , Robert J. Scherrer

A new method, based on the absorption of very high-energy gamma-rays by the cosmic infrared background, is proposed to constrain the value of the Hubble constant. As this value is both fundamental for cosmology and still not very well…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-19 A. Gorecki , A. Barrau , J. Grain , E. Memola

Precise measurement of the Hubble parameter will enable stringent tests of the standard model for cosmology. Standard sirens, using the luminosity distances measured by gravitational-wave observations of compact binary mergers, are expected…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-06 Alberto Salvarese , Hsin-Yu Chen , Alberto Mangiagli , Nicola Tamanini

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 use the Constitution supernova, the baryon acoustic oscillation, the cosmic microwave background, and the Hubble parameter data to analyze the evolution property of dark energy. We obtain different results when we fit different baryon…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Yungui Gong , Rong-Gen Cai , Yun Chen , Zong-Hong Zhu

Given a class of dark energy models, constraints from one set of cosmic acceleration observables make predictions for other observables. Here we present the allowed ranges for the expansion rate H(z), distances D(z), and the linear growth…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-23 Michael J. Mortonson , Wayne Hu , Dragan Huterer

Based on the assumption that some apparent properties of the observable universe are accurate at a reasonable level of approximation, a tentative is made to independently derive the values of the baryon density parameter, the Hubble…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 A. Dinculescu

We investigate the origin of $\Lambda$CDM parameter constraints in weak lensing, with a focus on the Hubble constant. We explain why current cosmic shear data are sensitive to the parameter combination $S_8 \propto \sigma_8 \Omega_m^{0.5}$,…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-30 Alex Hall

In this article, we investigate a new parametrization of the dark energy equation of state (EoS) with a single parameter for a barotropic fluid that deviates from the standard $\Lambda$CDM cosmology. We derive observational constraints on…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-31 D. Revanth Kumar , Santosh Kumar Yadav

In earlier papers we showed that a frame dependent effective action motivated by the postulates of three-space general coordinate invariance and Weyl scaling invariance exactly mimics a cosmological constant in Friedmann-Robertson-Walker…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-25 Stephen L. Adler

In this paper, we examine observational constraints on the power law cosmology; essentially dependent on two parameters $H_0$ (Hubble constant) and $q$ (deceleration parameter). We investigate the constraints on these parameters using the…

General Relativity and Quantum Cosmology · Physics 2015-03-20 Sarita Rani , A. Altaibayeva , M. Shahalam , J. K. Singh , R. Myrzakulov

A new method is proposed to measure the Hubble constant H0 through the mean transmitted flux observed from high redshift quasars. A semi-analytical model for the cosmological-independent volume density distribution function is adopted which…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-19 V. C. Busti , R. N. Guimarães , J. A. S. Lima

We use simulated Hubble parameter data in the redshift range 0 \leq z \leq 2 to explore the role and power of observational H(z) data in constraining cosmological parameters of the {\Lambda}CDM model. The error model of the simulated data…

Cosmology and Nongalactic Astrophysics · Physics 2011-03-11 Cong Ma , Tong-Jie Zhang

The redshift dependence of the cosmic microwave background temperature, $T(z)=T_0(1+z)$, is a key prediction of standard cosmology, but this relation is violated in many extensions thereof. Current astrophysical facilities can probe it in…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-09 C. J. A. P. Martins , A. M. M. Vieira

We investigate observational constraints on cosmological parameters combining 15 measurements of the transversal BAO scale (obtained free of any fiducial cosmology) with Planck-CMB data to explore the parametric space of some cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-10 Rafael C. Nunes , Santosh K. Yadav , J. F. Jesus , Armando Bernui
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