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Considering perturbation growth in spherical Top-Hat model of structure formation in a generalized Chaplygin gas dominated universe, we want to study this scenario with a modified Chaplygin gas model. The evolution of background and…

General Relativity and Quantum Cosmology · Physics 2015-05-11 S. Karbasi , H. Razmi

In this paper, we consider an open system from the thermodynamic perspective for an adiabatic FRW universe model in which particle creation occurs within the system. In that case, the modified continuity equation is obtained and then we…

General Relativity and Quantum Cosmology · Physics 2022-12-14 S. Ganjizadeh , Alireza Amani , M. A. Ramzanpour

We consider the quantum birth of a hot FRW universe from a vacuum-dominated quantum fluctuation with admixture of radiation and strings, which correspond to quantum tunnelling from a discrete energy level with a non-zero temperature. The…

General Relativity and Quantum Cosmology · Physics 2007-05-23 I. G. Dymnikova , M. L. Fil'chenkov

Recently, Tsallis, R\'{e}nyi and Sharma-Mitall and entropies have widely been used to study the gravitational and cosmological setups. We consider a flat FRW universe with linear interaction between dark energy and dark matter. We discuss…

General Physics · Physics 2019-01-08 M. Younas , Abdul Jawad , Saba Qummer , H. Moradpour , Shamaila Rani

We propose a new scenario for the early universe where there is a smooth transition between an early de Sitter-like phase and a radiation dominated era. In this model, the matter content is modelled by a new type of generalised Chaplygin…

Cosmology and Nongalactic Astrophysics · Physics 2010-03-16 Mariam Bouhmadi-Lopez , Pedro Frazao , Alfredo B. Henriques

A FRWL cosmological model with perfect fluid comprising of van der Waals gas and dust has been studied in the context of dynamical analysis of a three-component autonomous non-linear dynamical system for the particle number density $n$, the…

General Relativity and Quantum Cosmology · Physics 2019-02-12 Rossen I. Ivanov , Emil M. Prodanov

Time-evolution of the Universe as described by the Friedmann equation can be coupled to equations of motion of matter fields. Quantum effects may be incorporated to improve these classical equations of motion by the renormalization group…

High Energy Physics - Theory · Physics 2024-10-08 Istvan Gabor Marian , Andrea Trombettoni , Istvan Nandori

We determine the thermal evolution of the intergalactic medium (IGM) over $3\, \mathrm{Gyr}$ of cosmic time $1.8<z<5.4$ by comparing measurements of the Ly{\alpha} forest power spectrum to a suite of $\sim70$ hydrodynamical simulations. We…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-13 Michael Walther , Jose Oñorbe , Joseph F. Hennawi , Zarija Lukić

The equation of state of Chaplygin Gas is one of the simplest ways to illustrate dark energy effects during the late time. Indeed, while one uses the equation of state of Chaplygin Gas, the continuity equation gives specific energy density…

General Physics · Physics 2018-07-20 H. R. Fazlollahi

In this paper, we consider a recently proposed model of Dark Energy (DE) know as Modified Holographic Ricci DE (MHRDE) (which is function of the Hubble parameter and its first derivative with respect to the cosmic time $t$) in the light of…

General Physics · Physics 2017-05-31 Antonio Pasqua , Surajit Chattopadhyay , Iuliia Khomenko

In this paper, we have presented a model of the FLRW universe filled with matter and dark energy fluids, by assuming an ansatz that deceleration parameter is a linear function of the Hubble constant. This results in a time-dependent DP…

General Relativity and Quantum Cosmology · Physics 2021-08-02 Gopi Kant Goswami , Anirudh Pradhan , Aroonkumar Beesham

Observations of the rest-frame far-infrared (far-IR) emission of galaxies suggest a mild increase of dust temperature $T_{\rm dust}$ with redshift, although constraining $T_{\rm dust}$ in high-redshift systems remains challenging due to…

We study the temperature structure of the intergalactic medium (IGM) using a large cosmological N-body/SPH simulation. We employ a two-temperature model for the thermal evolution of the ionized gas, in which the relaxation process between…

Astrophysics · Physics 2009-11-10 Naoki Yoshida , Steven Furlanetto , Lars Hernquist

The present work deals with homogeneous and isotropic FLRW model of the Universe having a system of non-interacting diffusive cosmic fluids with barotropic equation of state (constant or variable equation of state parameter). Due to…

General Relativity and Quantum Cosmology · Physics 2019-02-22 Subhayan Maity , Pritikana Bhandari , Subenoy Chakraborty

The cosmic microwave background temperature is a cornerstone astrophysical observable. Its present value is tightly constrained, but its redshift dependence, which can now be determined until redshift $z\sim6.34$, is also an important probe…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-23 L. Gelo , C. J. A. P. Martins , N. Quevedo , A. M. M. Vieira

In this paper, after reconstructing the redshift evolution of the Hubble function by adopting Gaussian process techniques, we estimate the best-fit parameters for some flat Friedmann cosmological models based on a Modified Chaplygin Gas…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-28 Muhsin Aljaf , Daniele Gregoris , Martiros Khurshudyan

We analyze the global nonlinear stability of FRW (Friedmann-Robertson-Walker) spacetimes in presence of an irrotational perfect fluid. We assume that the fluid is governed by the so-called (generalized) Chaplygin equation of state relating…

General Relativity and Quantum Cosmology · Physics 2015-12-14 Philippe G. LeFloch , Changhua Wei

According to the photo-heating model of the intergalactic medium (IGM), He II reionization is expected to affect its thermal evolution. Evidence for additional energy injection into the IGM has been found at $3\lesssim z\lesssim4$, though…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Elisa Boera , Michael T. Murphy , George D. Becker , James S. Bolton

The thermal history of a large class of running vacuum models in which the effective cosmological term is described by a truncated power series of the Hubble rate, whose dominant term is $\Lambda (H) \propto H^{n+2}$, is discussed in…

General Relativity and Quantum Cosmology · Physics 2016-04-29 J. A. S. Lima , Spyros Basilakos , Joan Solà

Panchromatic analysis of galaxy spectral energy distributions, spanning from the ultraviolet to the far-infrared, probes not only the stellar population but also the properties of interstellar dust through its extinction and long-wavelength…

Astrophysics of Galaxies · Physics 2023-09-07 G. T. Jones , E. R. Stanway
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