Results 71 to 80 of about 2,969 (164)

COSMOLOGICAL PERTURBATIONS IN PRESENCE OF SCALAR FIELDS

Odessa Astronomical Publications, 2014
We investigate the role of the scalar field assuming its presence at late stages of the Universe evolution together with dust presented by a system of an arbitrary number of gravitating masses (galaxies, groups of galaxies and clusters of galaxies) and ...
A. Yu. Burgazli, M. Eingorn, A. Zhuk
doaj   +1 more source

Cosmic evolution beyond the singularity: a study of viscous bounce dynamics in F(R) theory

European Physical Journal C: Particles and Fields
This paper studies the impact of bulk viscosity on the feasibility of the cosmological bounce solutions in the framework of F(R) theory. In this perspective, the behavior of an isotropic homogeneous universe with a perfect matter configuration and new ...
M. Sharif, Eman M Moneer, Nusrat Fatima, Euaggelos E. Zotos   +3 more
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Dynamics of cosmological phase crossover during Bose–Einstein condensation of dark matter in Tsallis cosmology

European Physical Journal C: Particles and Fields
During the cosmic evolution process, as the temperature of a cosmological boson gas falls below a certain threshold, a Bose–Einstein condensation process can occur at various points throughout the cosmic history of the Universe.
Subhra Mondal, Amitava Choudhuri
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Neutrino Mass from Cosmology

Advances in High Energy Physics, 2012
Neutrinos can play an important role in the evolution of the universe, modifying some of the cosmological observables. In this contribution we summarize the main aspects of cosmological relic neutrinos, and we describe how the precision of present ...
Julien Lesgourgues, Sergio Pastor
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Viable inflationary models in a ghost-free Gauss–Bonnet theory of gravity

European Physical Journal C: Particles and Fields, 2019
In this work we investigate the inflationary phenomenological implications of a recently developed ghost-free Gauss–Bonnet theory of gravity. The resulting theory can be viewed as a scalar Einstein–Gauss–Bonnet theory of gravity, so by employing the ...
Shin’ichi Nojiri, S. D. Odintsov, V. K. Oikonomou, N. Chatzarakis, Tanmoy Paul   +4 more
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Hierarchical Cosmological Constraints through a Strong-lensing Distance Ratio

The Astrophysical Journal Supplement Series
Strong gravitational lensing provides an independent and powerful probe of cosmic expansion by directly linking observables to cosmological distances.
Shuaibo Geng, Shuo Cao, Marek Biesiada, Xinyue Jiang, Yalong Nan, Chenfa Zheng   +5 more
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Theoretical insights and implications of bouncing cosmology in $$f(\mathcal {R},\textrm{T}^2)$$ f ( R , T 2 ) theory

European Physical Journal C: Particles and Fields
In this paper, we explore cosmological bouncing solutions to investigate the cosmic evolution in the framework of energy-momentum squared gravity. We consider flat Friedmann–Robertson–Walker spacetime with a perfect matter distribution.
M. Sharif, M. Zeeshan Gul, I. Hashim
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Constraining Cosmological Parameters Using the Splashback Radius of Galaxy Clusters

The Astrophysical Journal
Cosmological parameters such as Ω _M and σ _8 can be measured indirectly using various methods, including galaxy cluster abundance and cosmic shear. These measurements constrain the composite parameter S _8 , leading to degeneracy between Ω _M and σ _8 .
Roan Haggar, Yuba Amoura, Charlie T. Mpetha, James E. Taylor, Kris Walker, Chris Power   +5 more
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Revealing some cosmological aspects of Kaniadakis entropy

Nuclear Physics B
Adopting the modifications induced by the truncated version of the Kaniadakis entropy on the Friedmann equations, we explore some relevant aspects of this cosmological scenario at the background level. We analyze the constraint imposed on the parameter K
Miguel Cruz, Samuel Lepe, Joel Saavedra
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The Cosmic Evolution of the Supermassive Black Hole Population: A Hybrid Observed Accretion and Simulated Mergers Approach

The Astrophysical Journal
Supermassive black holes (SMBHs) can grow through both accretion and mergers. It is still unclear how SMBHs evolve under these two channels from high redshifts to the SMBH population we observe in the local Universe.
Fan Zou, W. N. Brandt, Elena Gallo, Bin Luo, Qingling Ni, Yongquan Xue, Zhibo Yu   +6 more
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