scholarly journals Dark matter haloes in modified gravity and dark energy: interaction rate, small- and large-scale alignment

2017 ◽  
Vol 468 (3) ◽  
pp. 3174-3183 ◽  
Author(s):  
Benjamin L’Huillier ◽  
Hans A. Winther ◽  
David F. Mota ◽  
Changbom Park ◽  
Juhan Kim
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Modified Gravity ◽  
Large Scale ◽  
Interaction Rate ◽  
Energy Interaction ◽  
Large Scale Alignment

scholarly journals FORMATION OF DARK MATTER HALOES IN A HOMOGENEOUS DARK ENERGY UNIVERSE

2010 ◽  
Vol 19 (08n10) ◽  
pp. 1397-1403
Author(s):  
L. MARASSI
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Large Scale ◽  
State Parameter ◽  
Mass Function ◽  
Accelerated Expansion ◽  
X Ray ◽  
Energy Models ◽  
Dark Energy Component ◽  
Standard Press

Several independent cosmological tests have shown evidences that the energy density of the universe is dominated by a dark energy component, which causes the present accelerated expansion. The large scale structure formation can be used to probe dark energy models, and the mass function of dark matter haloes is one of the best statistical tools to perform this study. We present here a statistical analysis of mass functions of galaxies under a homogeneous dark energy model, proposed in the work of Percival (2005), using an observational flux-limited X-ray cluster survey, and CMB data from WMAP. We compare, in our analysis, the standard Press–Schechter (PS) approach (where a Gaussian distribution is used to describe the primordial density fluctuation field of the mass function), and the PL (power–law) mass function (where we apply a non-extensive q-statistical distribution to the primordial density field). We conclude that the PS mass function cannot explain at the same time the X-ray and the CMB data (even at 99% confidence level), and the PS best fit dark energy equation of state parameter is ω = -0.58, which is distant from the cosmological constant case. The PL mass function provides better fits to the HIFLUGCS X-ray galaxy data and the CMB data; we also note that the ω parameter is very sensible to modifications in the PL free parameter, q, suggesting that the PL mass function could be a powerful tool to constrain dark energy models.

scholarly journals Reconstructing the dark matter and dark energy interaction scenarios from observations

2019 ◽  
Vol 26 ◽  
pp. 100383 ◽  
Author(s):  
Weiqiang Yang ◽  
Narayan Banerjee ◽  
Andronikos Paliathanasis ◽  
Supriya Pan
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Energy Interaction

scholarly journals Observational constraints of a new unified dark fluid and the H0 tension

2019 ◽  
Vol 490 (2) ◽  
pp. 2071-2085 ◽  
Author(s):  
Weiqiang Yang ◽  
Supriya Pan ◽  
Andronikos Paliathanasis ◽  
Subir Ghosh ◽  
Yabo Wu
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Early Time ◽  
Observational Constraints ◽  
Minimal Extension ◽  
Energy Evolution ◽  
The Universe ◽  
Different Sources

ABSTRACT Unified cosmological models have received a lot of attention in astrophysics community for explaining both the dark matter and dark energy evolution. The Chaplygin cosmologies, a well-known name in this group have been investigated matched with observations from different sources. Obviously, Chaplygin cosmologies have to obey restrictions in order to be consistent with the observational data. As a consequence, alternative unified models, differing from Chaplygin model, are of special interest. In the present work, we consider a specific example of such a unified cosmological model, that is quantified by only a single parameter μ, that can be considered as a minimal extension of the Λ-cold dark matter cosmology. We investigate its observational boundaries together with an analysis of the universe at large scale. Our study shows that at early time the model behaves like a dust, and as time evolves, it mimics a dark energy fluid depicting a clear transition from the early decelerating phase to the late cosmic accelerating phase. Finally, the model approaches the cosmological constant boundary in an asymptotic manner. We remark that for the present unified model, the estimations of H0 are slightly higher than its local estimation and thus alleviating the H0 tension.

scholarly journals Testing Gravity using Void Profiles

2014 ◽  
Vol 11 (S308) ◽  
pp. 555-560 ◽  
Author(s):  
Yan-Chuan Cai ◽  
Nelson Padilla ◽  
Baojiu Li
Keyword(s):  
Dark Matter ◽  
Gravitational Lensing ◽  
Modified Gravity ◽  
Large Scale ◽  
Line Of Sight ◽  
Number Density ◽  
Density Profiles ◽  
Photometric Redshift ◽  
Redshift Survey ◽  
Near Future

AbstractWe investigate void properties inf(R)models using N-body simulations, focusing on their differences from General Relativity (GR) and their detectability. In the Hu-Sawickif(R)modified gravity (MG) models, the halo number density profiles of voids are not distinguishable from GR. In contrast, the samef(R)voids are more empty of dark matter, and their profiles are steeper. This can in principle be observed by weak gravitational lensing of voids, for which the combination of a spectroscopic redshift and a lensing photometric redshift survey over the same sky is required. Neglecting the lensing shape noise, thef(R)model parameter amplitudesfR0=10-5and 10-4may be distinguished from GR using the lensing tangential shear signal around voids by 4 and 8 σ for a volume of 1 (Gpc/h)3. The line-of-sight projection of large-scale structure is the main systematics that limits the significance of this signal for the near future wide angle and deep lensing surveys. For this reason, it is challenging to distinguishfR0=10-6from GR. We expect that this can be overcome with larger volume. The halo void abundance being smaller and the steepening of dark matter void profiles inf(R)models are unique features that can be combined to break the degeneracy betweenfR0and σ8.

scholarly journals Addressing the high-f problem in pseudo-Nambu–Goldstone boson dark energy models with dark matter–dark energy interaction

2020 ◽  
Vol 80 (10) ◽  
Author(s):  
Upala Mukhopadhyay ◽  
Avik Paul ◽  
Debasish Majumdar
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Dark Energy Model ◽  
Goldstone Boson ◽  
The Other ◽  
Mass Limit ◽  
Energy Models ◽  
Energy Interaction ◽  
Energy Scenario ◽  
Type Potential

AbstractWe consider a dark energy scenario driven by a scalar field $$\phi $$ ϕ with a pseudo-Nambu–Goldstone boson (pNGB) type potential $$V(\phi )=\mu ^4 \left( 1+ \mathrm{cos}(\phi /f) \right) $$ V ( ϕ ) = μ 4 1 + cos ( ϕ / f ) . The pNGB originates out of breaking of spontaneous symmetry at a scale f close to Planck mass $$M_\mathrm{{pl}}$$ M pl . We consider two cases namely the quintessence dark energy model with pNGB potential and the other, where the standard pNGB action is modified by the terms related to Slotheon cosmology. We demonstrate that for this pNGB potential, high-f problem is better addressed when the interaction between dark matter and dark energy is taken into account and that Slotheon dark energy scenario works even better over quintessence in this respect. To this end, a mass limit for dark matter is also estimated.

scholarly journals Detecting ultralight axion dark matter wind with laser interferometers

2016 ◽  
Vol 26 (07) ◽  
pp. 1750063 ◽  
Author(s):  
Arata Aoki ◽  
Jiro Soda
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Modified Gravity ◽  
Laser Interferometer ◽  
Mass Range ◽  
Dark Matter Halo ◽  
Detector Signal ◽  
Modified Gravity Theory ◽  
Axion Field ◽  
Laser Interferometers

The ultralight axion with mass around [Formula: see text][Formula: see text]eV is known as a candidate of dark matter. A peculiar feature of the ultralight axion is oscillating pressure in time, which produces oscillation of gravitational potentials. Since the solar system moves through the dark matter halo at the velocity of about [Formula: see text], there exists axion wind, which looks like scalar gravitational waves for us. Hence, there is a chance to detect ultralight axion dark matter with a wide mass range by using laser interferometer detectors. We calculate the detector signal induced by the oscillating pressure of the ultralight axion field, which would be detected by future laser interferometer experiments. We also argue that the detector signal can be enhanced due to the resonance in modified gravity theory explaining the dark energy.

Observational and astrophysical cosmology: 1980–2018

2019 ◽  
pp. 375-423
Author(s):  
Malcolm S. Longair
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Cosmological Constant ◽  
Large Scale ◽  
Cosmological Parameters ◽  
Semiconductor Detectors ◽  
Empirical Knowledge ◽  
Global Geometry ◽  
The Universe ◽  
Large Scale Structure Formation

Since 1980, our empirical knowledge of the universe has advanced tremendously and precision cosmology has become a reality. These developments have been largely technology-driven, the result of increased computer power, new generations of telescopes for all wavebands, new types of semiconductor detectors, such as CCDs, and major investments by many nations in superb observing facilities. The discipline also benefitted from the influx of experimental and theoretical physicists into the cosmological arena. The accuracy and reliability of the values of the cosmological parameters has improved dramatically, many of them now being known to about 1%. The ΛCDM model provides a remarkable fit to all the observational data, demonstrating that the cosmological constant is non-zero and that the global geometry of the universe is flat. The underlying physics of galaxy and large-scale structure formation has advanced dramatically and demonstrated the key roles played by dark matter and dark energy.

Interacting cosmological viscous fluid with Little Rip and Pseudo Rip solutions in f(R) gravity

2018 ◽  
Vol 15 (02) ◽  
pp. 1850028 ◽  
Author(s):  
R. D. Boko ◽  
M. J. S. Houndjo ◽  
J. Tossa
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Equation Of State ◽  
Viscous Fluid ◽  
Modified Gravity ◽  
Infinite Time ◽  
Two Fluids ◽  
Viscosity Models ◽  
Time Singularities ◽  
Analytic Expressions

In this paper, we investigate the evolution of the equation of state of the interacting viscous dark energy in [Formula: see text] gravity. We first consider the case when the dark energy does not interact with the dark matter and after, the case where there is a coupling between these dark components. The viscosity and the interaction between the two fluids are parameterized by constants [Formula: see text] and [Formula: see text] respectively for which a detailed investigation on the cosmological implications has been done. In the later part of the paper, we explore some bulk viscosity models with Little and Pseudo Rip infinite time singularities within [Formula: see text] modified gravity. We obtain analytic expressions for characteristic properties of these cosmological models.

A study on the modified holographic Ricci dark energy in logarithmic f(T) gravity

2013 ◽  
Vol 91 (4) ◽  
pp. 351-354 ◽  
Author(s):  
Antonio Pasqua ◽  
Surajit Chattopadhyay
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Equation Of State ◽  
Energy Density ◽  
Modified Gravity ◽  
State Parameter ◽  
Ricci Dark Energy ◽  
Equation Of State Parameter ◽  
Interaction Term ◽  
The Universe

In this paper, we have studied and investigated the behavior of a modified holographic Ricci dark energy (DE) model interacting with pressureless dark matter (DM) under the theory of modified gravity, dubbed logarithmic f(T) gravity. We have chosen the interaction term between DE and DM in the form Q = 3γHρm and investigated the behavior of the torsion, T, the Hubble parameter, H, the equation of state parameter, ωDE, the energy density of DE, ρDE, and the energy density contribution due to torsion, ρT, as functions of the redshift, z. We have found that T increases with the redshift, z, H increases with the evolution of the universe, ωDE has a quintessence-like behavior, and both energy densities increase going from higher to lower redshifts.

Cosmology Today

Daedalus ◽  
2014 ◽  
Vol 143 (4) ◽  
pp. 125-133
Author(s):  
David N. Spergel
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Gravitational Lensing ◽  
Large Scale ◽  
Empty Space ◽  
Microwave Background ◽  
Astronomical Observations ◽  
Basic Parameters ◽  
Age Of The Universe ◽  
The Universe

We seem to live in a simple but strange universe. Our basic cosmological model fits a host of astronomical observations with only five basic parameters: the age of the universe, the density of atoms, the density of matter, the initial “lumpiness” of the universe, and a parameter that describes whether this lumpiness is more pronounced on smaller physical scales. Our observations of the cosmic microwave background fluctuations determine these parameters with uncertainties of only 1 to 2 percent. The same model also provides an excellent fit to the large-scale clustering of galaxies and gas, the properties of galaxy clusters, observations of gravitational lensing, and supernova-based measurements of the Hubble relation. This model implies that we live in a strange universe: atoms make up only 4 percent of the visible universe, dark matter makes up 24 percent, and dark energy – energy associated with empty space – makes up 72 percent.

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