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We study Planck 2015 cosmic microwave background (CMB) anisotropy data using the energy density inhomogeneity power spectrum generated by quantum fluctuations during an early epoch of inflation in the non-flat XCDM model. Here dark energy…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-19 Junpei Ooba , Bharat Ratra , Naoshi Sugiyama

We investigate a phenomenological non-gravitational coupling between dark energy and dark matter, where the interaction in the dark sector is parameterized as an energy transfer either from dark matter to dark energy or the opposite. The…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-11 Riccardo Murgia , Stefano Gariazzo , Nicolao Fornengo

The emergence of an increasingly strong tension between the Hubble rate inferred from early- and late-time observations has reinvigorated interest in nonstandard scenarios, with the aim of reconciling these measurements. One such model…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-09 Matteo Lucca , Deanna C. Hooper

We examine the validity of the $\Lambda$CDM model, and probe for the dynamics of dark energy using latest astronomical observations. Using the $Om(z)$ diagnosis, we find that different kinds of observational data are in tension within the…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-14 Yuecheng Zhang , Hanyu Zhang , Dandan Wang , Yanghan Qi , Yuting Wang , Gong-Bo Zhao

The $\Lambda$CDM concordance cosmological model provides a remarkably successful description of the formation and evolution of structure in the Universe. However, a growing discrepancy between measurements of the expansion rate $H_0$ from…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-10 Isaque Dutra , Colin J. Burke , Priyamvada Natarajan , Weixiang Yu

We investigate whether the recent DESI DR2 measurements provide or not evidences for dynamical dark energy by exploring the $\omega_0\omega_a$CDM model and its extensions with free $\sum m_{\nu}$ and $N_{\mathrm{eff}}$. Using a…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-25 Salvatore Capozziello , Himanshu Chaudhary , Tiberiu Harko , Ghulam Mustafa

We investigate the constraints on cosmological parameters especially for EoS of dark energy, inflationary parameters, neutrino mass and curvature of universe using simulated Planck data. Firstly we determine cosmological parameters with…

Astrophysics · Physics 2014-11-18 Jun-Qing Xia , Hong Li , Gong-Bo Zhao , Xinmin Zhang

We combine complementary datasets from Cosmic Microwave Background (CMB) anisotropy measurements, high redshift supernovae (SN-Ia) observations and data from local cluster abundances and galaxy clustering (LSS) to constrain the dark energy…

Astrophysics · Physics 2009-11-07 Rachel Bean , Alessandro Melchiorri

Time delays between multiple images of lensed sources can probe the geometry of the universe. We propose a novel method based on free-form modelling of gravitational lenses to estimate time-delay distances and, in turn, cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Mauro Sereno , Danuta Paraficz

Cold New Early Dark Energy (Cold NEDE) addresses the Hubble tension through a triggered vacuum phase transition in the dark sector. In this paper, we constrain a phenomenological fluid model using recent cosmic microwave background…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-16 Aleksandr Chatrchyan , Florian Niedermann , Vivian Poulin , Martin S. Sloth

We constrain the evolution of dark matter energy density over time, specifically focusing on deviation from the standard model represented by the equation $\rho_{m}\propto(1+z)^{3-\varepsilon}$, where $\varepsilon$ is a constant parameter.…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-30 Yupeng Yang , Xinyi Dai , Yicheng Wang

We use the current weak lensing data to constrain the equation of state of dark energy $w$ and the total mass of massive neutrinos $\sum m_{\nu}$. The constraint on $w$ would be weak if only the current weak lensing data are used. With the…

Astrophysics · Physics 2008-10-21 Yan Gong , Tong-Jie Zhang , Tian Lan , Xue-Lei Chen

This short review examines recent progress in understanding dark matter, dark energy, and galactic halos using theory that departs minimally from standard particle physics and cosmology. Strict conformal symmetry (local Weyl scaling…

General Physics · Physics 2015-06-11 Robert K. Nesbet

We use observational data from Type Ia Supernovae (SN), Baryon Acoustic Oscillations (BAO), Cosmic Microwave Background (CMB) and observational Hubble data (OHD), and the Markov Chain Monte Carlo (MCMC) method, to constrain the cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-13 Jianbo Lu , Emmanuel N. Saridakis , M. R. Setare , Lixin Xu

We have studied constraints on the equation of state, $w$, and speed of sound, c_s, of the dark energy from a joint analysis of data from the cosmic microwave background, large scale structure and type-Ia supernovae. We find that current…

Astrophysics · Physics 2009-11-10 Steen Hannestad

We study how the determination of the Hubble constant from cosmological distance measures is affected by models of dark energy and vice versa. For this purpose, constraints on the Hubble constant and dark energy are investigated using the…

Astrophysics · Physics 2008-11-26 Kazuhide Ichikawa , Tomo Takahashi

In this paper, we combine the the latest observational data, including the WMAP five-year data (WMAP5), the baryon acoustic oscillations (BAO) and type Ia supernovae (SN) "union" compilation, and use the Markov Chain Monte Carlo method to…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-11 Hong Li , Jun-Qing Xia

For the first time, we reconstruct the dark energy equation of the state parameter $w$ from the combination of background and perturbation observations, specifically combining the Hubble parameter data from cosmic chronometer observations…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-15 Bikash R. Dinda , Narayan Banerjee

Recently, Dark Energy Spectroscopic Instrument (DESI) collaboration based on their first year data has reported a $\gtrsim 3\sigma$ evidence for an evolving dark energy (DE) against the cosmological constant (CC), so the standard…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-21 Hao Wang , Yun-Song Piao

We investigate the observational constraints on the interacting holographic dark energy model. We consider five typical interacting models with the interaction terms $Q=3\beta H\rho_{\rm{de}}$, $Q=3\beta H\rho_{\rm{c}}$, $Q=3\beta…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-01 Lu Feng , Xin Zhang
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