scholarly journals Testing dark matter warmness and quantity via the reduced relativistic gas model

2012 ◽  
Vol 85 (2) ◽  
Author(s):  
Julio C. Fabris ◽  
Ilya L. Shapiro ◽  
A. M. Velasquez-Toribio
Keyword(s):  
Dark Matter ◽  
Relativistic Gas

scholarly journals On general features of warm dark matter with reduced relativistic gas

2018 ◽  
Vol 78 (5) ◽  
Author(s):  
W. S. Hipólito-Ricaldi ◽  
R. F. vom Marttens ◽  
J. C. Fabris ◽  
I. L. Shapiro ◽  
L. Casarini
Keyword(s):  
Dark Matter ◽  
Relativistic Gas

scholarly journals Analytical warm dark matter power spectrum on small scales

2021 ◽  
Vol 2021 (11) ◽  
pp. 062
Author(s):  
G. Pordeus-da-Silva ◽  
R.C. Batista ◽  
L.G. Medeiros
Keyword(s):  
Dark Matter ◽  
Power Spectrum ◽  
Sound Speed ◽  
System Of Equations ◽  
Matter Power Spectrum ◽  
Cosmological Context ◽  
Small Scales ◽  
Analytical Development ◽  
Relativistic Gas ◽  
The Ideal

Abstract Using the Reduced Relativistic Gas (RRG) model, we analytically determine the matter power spectrum for Warm Dark Matter (WDM) on small scales, k > 1 h/Mpc. The RRG is a simplified model for the ideal relativistic gas, but very accurate in the cosmological context. In another work, we have shown that, for typical allowed masses for dark matter particles, m>5 keV, the higher order multipoles, ℓ ≥ 2, in the Einstein-Boltzmann system of equations are negligible on scales k < 10 h/Mpc. Hence, we can follow the perturbations of WDM using the ideal fluid framework, with equation of state and sound speed of perturbations given by the RRG model. We derive a Mészáros-like equation for WDM and solve it analytically in radiation, matter and dark energy dominated eras. Joining these solutions, we get an expression that determines the value of WDM perturbations as a function of redshift and wavenumber. Then we construct the matter power spectrum and transfer function of WDM on small scales and compare it to some results coming from Lyman-α forest observations. Besides being a clear and pedagogical analytical development to understand the evolution of WDM perturbations, our power spectrum results are consistent with the observations considered and the other determinations of the degree of warmness of dark matter particles.

scholarly journals SIMPLE COSMOLOGICAL MODEL WITH RELATIVISTIC GAS

2005 ◽  
Vol 20 (35) ◽  
pp. 2723-2734 ◽  
Author(s):  
GUILHERME DE BERREDO-PEIXOTO ◽  
ILYA L. SHAPIRO ◽  
FLÁVIA SOBREIRA
Keyword(s):  
Dark Matter ◽  
Equation Of State ◽  
Cosmological Model ◽  
Analytic Solution ◽  
Elementary Function ◽  
Friedmann Equation ◽  
Massive Particles ◽  
Relativistic Gas ◽  
Complex Cases

We construct simple and useful approximation for the relativistic gas of massive particles. The equation of state is given by an elementary function and admits analytic solution of the Friedmann equation, including more complex cases when the relativistic gas of massive particles is considered together with radiation or with dominating cosmological constant. The model of relativistic gas may be interesting for the description of primordial Universe, especially as a candidate for the role of a Dark Matter.

Existence of RNA 'dark matter' in doubt

Nature ◽  
2010 ◽  
Author(s):  
Melissa Lee Phillips
Keyword(s):  
Dark Matter
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