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It is well known that estimating cosmological parameters from cosmic microwave background (CMB) data alone results in a significant degeneracy between the total neutrino mass and several other cosmological parameters, especially the Hubble…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-28 Will Sutherland

We present a comparison of void properties between the standard model of cosmology, $\Lambda$ Cold Dark Matter ($\Lambda$CDM), and two alternative cosmological models with evolving and interacting dark sectors: a quintessence model…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-03 Eromanga Adermann , Pascal J. Elahi , Geraint F. Lewis , Chris Power

We take a phenomenological approach to study the cosmological evolution of decaying vacuum cosmology ($\Lambda(t)$CDM) based on a simple assumption about the form of the modified matter expansion rate. In this framework, almost all the…

Astrophysics · Physics 2009-11-10 Peng Wang , Xin-He Meng

We investigate the viability of a cosmological scenario with interacting dark sector, which can describe the coexistence between dark energy and dark matter. The model possesses an analytical solution for the Hubble function and we…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-18 Shambel Sahlu , Andronikos Paliathanasis , Genly Leon , Amare Abebe

We use observational data from Type Ia Supernovae (SNIa), Baryon Acoustic Oscillations (BAO), and Cosmic Microwave Background (CMB), along with requirements of Big Bang Nucleosynthesis (BBN), to constrain the cosmological scenarios governed…

High Energy Physics - Theory · Physics 2015-05-14 Sourish Dutta , Emmanuel N. Saridakis

In this manuscript, we investigate the constraints on dynamical vacuum models within the framework of $\Lambda(t)$CDM cosmology by assuming a parameterization of the vacuum energy density as $\rho_{\Lambda}(t)=\rho_{\Lambda 0} \left[1 +…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-14 Yerlan Myrzakulov , M. Koussour , M. Bulanbay , S. Muminov , J. Rayimbaev

Interacting dark energy-dark matter models have been widely analyzed in the literature in an attempt to find traces of new physics beyond the usual cosmological ($\Lambda$CDM) models. Such a coupling between both dark components is usually…

General Relativity and Quantum Cosmology · Physics 2022-08-17 Diego Álvarez-Ortega , Gonzalo J. Olmo , Diego Rubiera-García , Diego Sáez-Chillón Gómez

A unification of dark matter and dark energy in terms of a logotropic perfect dark fluid has recently been proposed, where deviations with respect to the standard $\Lambda {\rm CDM}$ model are dependent on a single parameter $B$. In this…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-24 V. M. C. Ferreira , P. P. Avelino

The Fractal Bubble model has been proposed as a viable cosmology that does not require dark energy to account for cosmic acceleration, but rather attributes its observational signature to the formation of structure. In this paper it is…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-06 Juliana Kwan , Matthew J. Francis , Geraint F. Lewis

An alternative to the postulate of dark energy required to explain the accelerated expansion of the universe is to adopt an inhomogeneous cosmological model to explain the supernovae data without dark energy. We adopt a void cosmology…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-02 J. W. Moffat

In this study, we consider three dark energy models in which $\Lambda$ is not constant, but has a dynamic nature that depends on the Hubble parameter $H$ and/or its time derivative $\dot{H}$. We analyze the generalized running vacuum model,…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-05 Christine R. Farrugia , Joseph Sultana , Jurgen Mifsud

We study a generalized version of Chaplygin gas as unified model of dark matter and dark energy. Using realistic theoretical models and the currently available observational data from the age of the universe, the expansion history based on…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-15 Chan-Gyung Park , Jai-chan Hwang , Jaehong Park , Hyerim Noh

In the CDM paradigm, the halo mass function is a sensitive probe of the cosmic structure. In observations, halo mass is typically estimated from its relation with other observables. The resulting halo mass function is subject to systematic…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-09 Fuyu Dong , Jun Zhang , Xiaohu Yang , Jiajun Zhang , Wentao Luo

Consistent observations indicate that some of the important cosmological parameters measured through the local observations are in huge tension with their measurements from the global observations (within the minimal $\Lambda$CDM…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-22 Supriya Pan , Weiqiang Yang , Eleonora Di Valentino , Arman Shafieloo , Subenoy Chakraborty

We perform a thorough examination of the neutrino mass ($M_\nu$) constraints achievable by combining future spectroscopic galaxy surveys with cosmic microwave background (CMB) experiments, focusing on the contribution of CMB lensing and…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-26 Aoife Boyle

Current and upcoming surveys will measure the cosmological parameters with an extremely high accuracy. The primary goal of these observations is to eliminate some of the currently viable cosmological models created to explain the late time…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Savvas Nesseris , Domenico Sapone

Recently H(z) data obtained from differential ages of galaxies have been proposed as a new geometrical probe of dark energy. In this paper we use those data, combined with other background tests (CMB shift and SNIa data), to constrain a set…

Astrophysics · Physics 2009-11-13 Ruth Lazkoz , Elisabetta Majerotto

We present and constrain a cosmological model where the only component is a pressureless fluid with bulk viscosity as an explanation for the present accelerated expansion of the universe. We study the particular model of a bulk viscosity…

General Relativity and Quantum Cosmology · Physics 2009-01-05 Arturo Avelino , Ulises Nucamendi

The dark energy problem has led to speculation that not only may LCDM be wrong, but that the FLRW models themselves may not even provide the correct family of background models. We discuss how direct measurements of H(z) can be used to…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-12 Arman Shafieloo , Chris Clarkson

Ordinary 3D Baryon Acoustic Oscillations (BAO) data are model-dependent, requiring the assumption of a cosmological model to calculate comoving distances during data reduction. Throughout the present-day literature, the assumed model is…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-01 Sowmaydeep Dwivedi , Marcus Högås
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