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The Hubble constant $H_0$ tension has emerged as the most serious crisis in modern cosmology, potentially indicating that the $\Lambda$CDM model may not describe our universe accurately. In this paper, we establish a new,…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-26 Yang Liu , Bao Wang , Hongwei Yu , Puxun Wu

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

The accelerating expansion of the universe is one of the most profound discoveries in modern cosmology, pointing to a universe in which 70% of the mass-energy density has an unknown form spread uniformly across the universe. This result has…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-20 David Rubin , Brian Hayden

In this note, we consider the observational constraints on some cosmological models by using the 307 Union type Ia supernovae (SNIa), the 32 calibrated Gamma-Ray Bursts (GRBs) at $z>1.4$, the updated shift parameter $R$ from WMAP 5-year…

Astrophysics · Physics 2009-03-23 Hao Wei

We constrain three cosmological models, i.e. the concordance cold dark matter plus a cosmological constant ($\Lambda$CDM) model, Power-law (PL) model, and $R_h=ct$ model using the available local probes, which includes the JLA compilation…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-02 Hai-Nan Lin , Xin Li , Yu Sang

We probe the cosmic acceleration by using the recently released SNLS3 sample of 472 type Ia supernovae. Combining this type Ia supernovae dataset with the cosmic microwave background anisotropy data from the Wilkinson Microwave Anisotropy…

Cosmology and Nongalactic Astrophysics · Physics 2011-07-14 Xiao-Dong Li , Song Li , Shuang Wang , Wen-Shuai Zhang , Qing-Guo Huang , Miao Li

In this paper, we study the thermodynamical and mathematical consistencies for a non-singular early-time viscous cosmological model known as soft-Big Bang, which was previously found in [N. Cruz, E. Gonz\'alez, and J. Jovel, Phys. Rev. D…

General Relativity and Quantum Cosmology · Physics 2023-10-12 Norman Cruz , Esteban González , Jose Jovel

We consider the evolution of a flat Friedmann-Robertson-Walker Universe, filled with a causal bulk viscous cosmological fluid, in the presence of variable gravitational and cosmological constants. The basic equation for the Hubble…

General Relativity and Quantum Cosmology · Physics 2008-11-26 M. K. Mak , J. A. Belinchon , T. Harko

We consider a Friedmann model of the universe with bulk viscous matter and radiation as the cosmic components. We study the asymptotic properties in the equivalent phase space by considering the three cases for the bulk viscous coefficient…

General Relativity and Quantum Cosmology · Physics 2019-05-13 Athira Sasidharan , Titus K Mathew

Non-zero neutrino mass would affect the evolution of the Universe in observable ways, and a strong constraint on the mass can be achieved using combinations of cosmological data sets. We focus on the power spectrum of cosmic microwave…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Toyokazu Sekiguchi , Kazuhide Ichikawa , Tomo Takahashi , Lincoln Greenhill

This paper examines a cosmological model of scale-dependent gravity. The gravitational action is taken to be the Einstein-Hilbert term supplemented with a cosmological constant, where the couplings, $G_k$ and $\Lambda_k$, run with the…

General Relativity and Quantum Cosmology · Physics 2024-05-29 Pedro D. Alvarez , Benjamin Koch , Cristobal Laporte , Angel Rincon

The phantom brane has several important distinctive features: (i) Its equation of state is phantom-like, but there is no future `big rip' singularity, (ii) the effective cosmological constant on the brane is dynamically screened, because of…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-08 Ujjaini Alam , Satadru Bag , Varun Sahni

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…

Cosmology and Nongalactic Astrophysics · Physics 2013-09-17 Muhammad Omer Farooq

Some cylindrically symmetric inhomogeneous viscous fluid cosmological models with electro-magnetic field are obtained. To get a solution a supplementary condition between metric potentials is used. The viscosity coefficient of bulk viscous…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Anirudh Pradhan , Sudhir Kumar Srivastav , Kanti R. Jotania

In this paper we summarise the constraints that low-redshift data --such as supernovae Ia (SN Ia), baryon acoustic oscillations (BAO) and cosmic chronometers (CC)-- are able to set on the concordance model and its extensions, as well as on…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-29 Vladimir V. Luković , Balakrishna S. Haridasu , Nicola Vittorio

The difference from 4 to 6 $\sigma$ in the Hubble constant ($H_0$) between the values observed with the local (Cepheids and Supernovae Ia, SNe Ia) and the high-z probes (CMB obtained by the Planck data) still challenges the astrophysics and…

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

The luminosity distance describing the effect of local inhomogeneities in the propagation of light proposed by Zeldovich-Kantowski-Dyer-Roeder (ZKDR) is tested with two probes for two distinct ranges of redshifts: supernovae Ia (SNe Ia) in…

Cosmology and Nongalactic Astrophysics · Physics 2013-04-03 Nora Bretón , Ariadna Montiel

A plane-symmetric non-static cosmological model representing a bulk viscous fluid distribution has been obtained which is inhomogeneous and anisotropic and a particular case of which is gravitationally radiative. Without assuming any {\it…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Anirudh Pradhan , Hare Ram Pandey