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The thermodynamic and dynamical properties of a variable dark energy model with density scaling as rho_x \propto (1+z)^m, z being the redshift, are discussed following the outline of Jetzer et al. This kind of models are proven to lead to…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-08 Philippe Jetzer , Crescenzo Tortora

The motivation of the present work is to reconstruct a dark energy model through the {\it dimensionless dark energy function} $X(z)$, which is the dark energy density in units of its present value. In this paper, we have shown that a scalar…

General Relativity and Quantum Cosmology · Physics 2017-02-01 Abdulla Al Mamon , Kazuharu Bamba , Sudipta Das

Baryonic oscillations in the galaxy power spectrum have been studied as a way of probing dark-energy models. While most studies have focused on spectroscopic surveys at high redshift, large multi-color imaging surveys have already been…

Astrophysics · Physics 2009-11-10 Derek Dolney , Bhuvnesh Jain , Masahiro Takada

We constrain cosmological parameters using only Hubble parameter data and quantify the impact of future Hubble parameter measurements on parameter estimation for the most typical dark energy models. We first constrain cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-27 Jia-Jia Geng , Rui-Yun Guo , Anzhong Wang , Jing-Fei Zhang , Xin Zhang

It is well known that flat FRW metric is a special case of Bianchi type I spacetime. In this paper, we use 38 Hubble parameter, $H(z)$, measurements at intermediate redshifts $0.07\leq z\leq 2.36$ and its joint combination with the latest…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-21 Hassan Amirhashchi

The influence of dark matter inhomogeneities on the angular size-redshift test is investigated for a large class of flat cosmological models driven by dark energy plus a cold dark matter component (XCDM model). The results are presented in…

Astrophysics · Physics 2009-06-23 R. C. Santos , J. A. S. Lima

In this paper, we constrain dark energy models using a compendium of observations at low redshifts. We consider the dark energy as a barotropic fluid, with the equation of state a constant as well the case where dark energy equation of…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-21 Ashutosh Tripathi , Archana Sangwan , H. K. Jassal

Reconstructing the expansion history of the Universe from type Ia supernovae data, we fit the growth rate measurements and put model-independent constraints on some key cosmological parameters, namely, $\Omega_\mathrm{m},\gamma$, and…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-10 Benjamin L'Huillier , Arman Shafieloo , Hyungjin Kim

We constrain the redshift dependence of (rest frame) host galaxy dispersion measures of localized Fast Radio Bursts (FRBs) by assuming it to vary as a simple power law ($\propto (1+z)^{\alpha}$). We simultaneously fit $\alpha$ as well as…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-13 Sandeep Kumar Acharya , Paz Beniamini

We use the Allen et al. (2004) Chandra measurements of x-ray gas mass fraction of 26 rich clusters to place constraints on the scalar-field dark energy model with inverse power law potential energy density. The constraints are consistent…

Astrophysics · Physics 2009-11-10 Gang Chen , Bharat Ratra

The energy density of a scalar field $\phi$ with potential $V(\phi) \propto \phi^{-\alpha}$, $\alpha > 0$, behaves like a time-variable cosmological constant that could contribute significantly to the present energy density. Predictions of…

Astrophysics · Physics 2009-10-31 Silviu Podariu , Bharat Ratra

We update constraints on cosmic opacity by combining recent SN Type Ia data compilation with the latest measurements of the Hubble expansion at redshifts between 0 and 2. The new constraint on the parameter $\epsilon$ parametrising…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Anastasios Avgoustidis , Clare Burrage , Javier Redondo , Licia Verde , Raul Jimenez

We consider the possible observation of Fast Radio Bursts (FRBs) with planned future radio telescopes, and investigate how well the dispersions and redshifts of these signals might constrain cosmological parameters. We construct mock…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-11 Anthony Walters , Amanda Weltman , B. M. Gaensler , Yin-Zhe Ma , Amadeus Witzemann

We investigate the possibility of a dark energy component that is scaling with epochs. A phenomenological model is introduced whose energy density depends on the redshift in such a way that a smooth transition among the three dominant…

Astrophysics · Physics 2009-11-10 Salvatore Capozziello , Alessandro Melchiorri , Alice Schirone

Cosmology in the near future promises a measurement of the sum of neutrino masses, a fundamental Standard Model parameter, as well as substantially-improved constraints on the dark energy. We use the shape of the BOSS redshift-space galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-09 Amol Upadhye

Fanaroff-Riley type IIb (FR IIb) radio galaxies provide a modified standard yardstick that allows constraints to be placed on global cosmological parameters. A sample of 20 FR IIb radio galaxies with redshifts between 0 and 2 are compared…

Astrophysics · Physics 2010-11-19 Ruth A. Daly , E. J. Guerra

We examine the constraints that satellite-acquired Type Ia and IIP supernova apparent magnitude versus redshift data will place on cosmological model parameters in models with and without a constant or time-variable cosmological constant…

Astrophysics · Physics 2009-10-31 Silviu Podariu , Peter Nugent , Bharat Ratra

There are many different approaches to using observations to constrain or determine the global cosmological parameters that describe our universe. Methods that rely upon a determination of the coordinate distance to high-redshift sources…

Astrophysics · Physics 2009-11-07 Ruth A. Daly , Matthew P. Mory , Erick J. Guerra

Recent studies of radio data put strong constraints on annihilation cross section for dark matter. In this article, we provide the first analysis of using M33 radio data in constraining annihilating dark matter. The resulting constraints of…

High Energy Astrophysical Phenomena · Physics 2017-10-24 Man Ho Chan

In this work we study the magnitude-redshift relation of a non-standard cosmological model. The model under consideration was firstly investigated within a special case of metric-affine gravity (MAG) and was recently recovered via different…

General Relativity and Quantum Cosmology · Physics 2009-04-03 Dirk Puetzfeld , Xuelei Chen