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相关论文: Constraints on kinematic models from the latest ob…

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We have performed the dynamical system analysis to obtain the critical point in which, the value of the geometric and dynamical parameters satisfy the late-time cosmic behavior of the Universe. At the outset, the modified Friedmann…

广义相对论与量子宇宙学 · 物理学 2025-10-30 Rahul Bhagat , B. Mishra

We present and employ a new kinematical approach to cosmological `dark energy' studies. We construct models in terms of the dimensionless second and third derivatives of the scale factor a(t) with respect to cosmic time t, namely the…

天体物理学 · 物理学 2008-11-26 David Rapetti , Steven W. Allen , Mustafa A. Amin , Roger D. Blandford

This paper introduces a novel cosmological model aimed at probing the accelerated expansion of the late Universe through a unique parametrization of the deceleration parameter. We aim to constrain key cosmic parameters by integrating recent…

广义相对论与量子宇宙学 · 物理学 2024-08-14 Himanshu Chaudhary , Ujjal Debnath , G. Mustafa , S. K. Maurya , Farruh Atamurotov

The fitting of the observed redshifts and magnitudes of type Ia supernovae to what we would see in homogeneous cosmological models has led to constraints on cosmological parameters. However, in doing such fits it is assumed that the sampled…

天体物理学 · 物理学 2010-11-11 R. Ali Vanderveld

Cosmic acceleration is investigated through a kink-like expression for the deceleration parameter (q). The new parametrization depends on the initial (q_i) and final (q_f) values of q, on the redshift of the transition from deceleration to…

天体物理学 · 物理学 2009-06-23 Emille E. O. Ishida , Ribamar R. R. Reis , Alan V. Toribio , Ioav Waga

We investigate observational constraints from present and future supernova data on a large class of decaying vacuum cosmologies. In such scenarios the present value of the vacuum energy density is quantified by a positive $\beta$ parameter…

天体物理学 · 物理学 2009-11-07 J. S. Alcaniz , J. M. F. Maia

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…

宇宙学与河外天体物理 · 物理学 2015-05-18 Anastasios Avgoustidis , Clare Burrage , Javier Redondo , Licia Verde , Raul Jimenez

We place novel constraints on the cosmokinetic parameters by using a joint analysis of the newest VLT-KMOS HII galaxies (HIIG) with the Supernovae Type Ia (SNIa) Pantheon sample. We combine the latter datasets in order to reconstruct, in a…

We apply the Union2 compilation of 557 supernova Ia data, the baryon acoustic oscillation measurement of distance, the cosmic microwave background radiation data from the seven year Wilkinson Microwave Anisotropy Probe, and the Hubble…

宇宙学与河外天体物理 · 物理学 2011-07-27 Yungui Gong , Xiao-ming Zhu , Zong-Hong Zhu

Current error estimates on kinematic parameters are based on the assumption that the data points in the spectra follow a Poisson distribution. For realistic data that have undergone several steps in a reduction process, this is generally…

天体物理学 · 物理学 2009-11-07 V. De Bruyne , P. Vauterin , S. De Rijcke , H. Dejonghe

The newly released observational $H(z)$ data (OHD) is used to constrain $\Lambda(t)$CDM models as holographic and agegraphic dark energy. By the use of the length scale and time scale as the IR cut-off including Hubble horizon (HH), future…

宇宙学与河外天体物理 · 物理学 2011-09-13 Zhong-Xu Zhai , Tong-Jie Zhang , Wen-Biao Liu

Motivated by the fact that calibrated light curves of Type Ia supernovae (SNe Ia) have become a major tool to determine the expansion history of the Universe, considerable attention has been given to, both, observations and models of these…

宇宙学与河外天体物理 · 物理学 2013-02-27 W. Hillebrandt , M. Kromer , F. K. Röpke , A. J. Ruiter

In this paper, we present a kinematic analysis of the Universe's expansion history using cosmography, with a particular emphasis on the jerk parameter $j_0$, which is equal to one in the standard $\Lambda$CDM scenario. We use distance…

宇宙学与河外天体物理 · 物理学 2025-10-02 Gabriel Rodrigues , Rayff de Souza , Jailson Alcaniz

The existence of inhomogeneities in the observed Universe modifies the distance-redshift relations thereby affecting the results of cosmological tests in comparison to the ones derived assuming spatially uniform models. By modeling the…

宇宙学与河外天体物理 · 物理学 2015-06-04 V. C. Busti , R. C. Santos , J. A. S. Lima

In this paper, a well-motivated parametrization of the Hubble parameter ($H$% ) is revisited that renders two models of dark energy showing some intriguing features of the late-time accelerating Universe. A general quintessence field is…

广义相对论与量子宇宙学 · 物理学 2023-09-19 Amine Bouali , Himanshu Chaudhary , Amritansh Mehrotra , S. K. J. Pacif

In this paper, we constrain the Cardassian expansion models from the latest observations including the updated Gamma-ray bursts (GRBs), which calibrated cosmology-independently from the Union2 compilation of type Ia supernovae (SNe Ia). By…

宇宙学与河外天体物理 · 物理学 2015-05-19 Nan Liang , Puxun Wu , Zong-Hong Zhu

Model-independent estimations for the spatial curvature not only provide a test for the fundamental Copernican principle assumption, but also can effectively break the degeneracy between curvature and dark energy properties. In this paper,…

宇宙学与河外天体物理 · 物理学 2016-12-28 Zhengxiang Li , Guo-Jian Wang , Kai Liao , Zong-Hong Zhu

In this paper, we propose a new parametrization of $Om(z)$ diagnostics and show how the most recent and significantly improved observations concerning the $H(z)$ and SN Ia measurements can be used to probe the consistency or tension between…

宇宙学与河外天体物理 · 物理学 2018-06-13 Jing-Zhao Qi , Shuo Cao , Marek Biesiada , Tengpeng Xu , Yan Wu , Sixuan Zhang , Zong-Hong Zhu

There are several studies proposing phenomenological consequences of a deformation of special and general relativity. Here, we cast novel constraints on the deformation parameter of a metric in the cotangent bundle accounting for a curved…

广义相对论与量子宇宙学 · 物理学 2020-11-18 J. J. Relancio , S. Liberati

The expansion rate of the Universe changes with time, initially slowing (decelerating) when the universe was matter dominated, because of the mutual gravitational attraction of all the matter in it, and more recently speeding up…

宇宙学与河外天体物理 · 物理学 2013-09-17 Muhammad Omer Farooq