Observational constraints on interacting dark energy models with multiple measurements of quasars

In this work, I shall figure out the general structure of dark fabric matter, and the direct interactions of the celestial objects, ordinary matter, and ordinary energy with dark fabric matter and energy. Dark Fabric matter and energy is a hidden dimension of the parallel universes, visible Universe, galaxies, Atoms, molecules, ordinary matter, celestial objects, stellar systems, and Planetary systems. The Main Structure of Dark fabric matter consists of the Dark matter particles called Fabriton particles, Dark Matter Strings, and Dark Matter Webs. The dark matter particles are named fabriton particles. Fabriton means Fast actively binding reacting in total objects naturally. Fabriton is a good proposed name for dark matter particles to be recognized among subatomic particles. The mystery of Dark matter and the dark energy could be solved here entirely. Einstein and Newton built clear mathematical equations to describe the nature of gravity, after them many other people worked warmly to resolve the reality of gravity, dark matter, and dark energy. Gravity is the ripples, curvatures, gravitational waves, and tunnels that form rapidly in the structure of dark fabric matter and energy when celestial objects and ordinary matter particles pass through it directly.

In order to test the possible interaction between dark energy and dark\nmatter, we investigate observational constraints on a phenomenological\nscenario, in which the ratio between the dark energy and matter densities is\nproportional to the power law case of the scale factor, $r\\equiv\n(\\rho_X/\\rho_m)\\propto a^{\\xi}$. By using the Markov chain Monte Carlo method,\nwe constrain the phenomenological interacting dark energy model with the newly\nrevised $H(z)$ data, as well as the cosmic microwave background (CMB)\nobservation from the 7-year Wilkinson Microwave Anisotropy Probe (WMAP7)\nresults, the baryonic acoustic oscillation (BAO) observation from the\nspectroscopic Sloan Digital Sky Survey (SDSS) data release 7 (DR7) galaxy\nsample and the type Ia supernovae (SNe Ia) from Union2 set. The best-fit values\nof the model parameters are\n$\\Omega_{m0}=0.27_{-0.02}^{+0.02}(1\\sigma)_{-0.03}^{+0.04}(2\\sigma)$,\n$\\xi=3.15_{-0.50}^{+0.48}(1\\sigma)_{-0.71}^{+0.72}(2\\sigma)$, and\n$w_X=-1.05_{-0.14}^{+0.15}(1\\sigma)_{-0.21}^{+0.21}(2\\sigma)$, which are more\nstringent than previous results. These results show that the standard\n$\\Lambda$CDM model without any interaction remains a good fit to the recent\nobservational data; however, the interaction that the energy transferring from\ndark matter to dark energy is slightly favored over the interaction from dark\nenergy to dark matter. It is also shown that the $H(z)$ data can give more\nstringent constraints on the phenomenological interacting scenario when\ncombined to CMB and BAO observations, and the confidence regions of\n$H(z)$+BAO+CMB, SNe+BAO+CMB, and $H(z)$+SNe+BAO+CMB combinations are consistent\nwith each other.\n

Cosmological models with running cosmological term and decaying dark matter

The interacting dark matter (IDM) scenario allows for the acceleration of the Universe without Dark Energy. We constrain the IDM model by using the newly revised observational data including $H(z)$ data and Union2 SNe Ia via the Markov chain Monte Carlo method. When mimicking the $\Lambda$CDM model, we obtain a more stringent upper limit to the effective annihilation term at $\kappa C_1\approx 10^{-3.4}\rm{Gyr}^{-1}$, and a tighter lower limit to the relevant mass of Dark Matter particles at $M_x\approx 10^{-8.6}\rm{Gev}$. When mimicking the $w$CDM model, we find that the effective equation of state of IDM is consistent with the concordance $\Lambda$CDM model and appears to be most consistent with the effective phantom model with a constant EoS for which $w<-1$.

The paper brings a novel approach to unification of dark matter and dark energy in terms of a cosmic fluid. A model is introduced in which the cosmic fluid speed of sound squared is defined as a function of its equation of state (EoS) parameter. It is shown how logarithmic part of this function results in dynamical regimes previously not observed in cosmic fluid models. It is shown that in a particular dynamical regime the model behaves as a unification of dark matter and phantom dark energy. Further, it is shown that the model may describe dark matter - dark energy unification in which dark energy asymptotically behaves as dark energy with a constant EoS parameter larger than −1. In a specific parameter regime the unified fluid model also reproduces global expansion similar to ΛCDM model with fluid speed of sound vanishing for small scale factor values and being small, or even vanishing, for large scale factor values. Finally, it is shown how the model may be instrumental in describing the cosmic fluid dark matter-dark energy-dark matter unification. Physical constraints on model parameters yielding such transient dark energy behavior are obtained.

Dark energy and dark matter

Models where the dark matter component of the Universe interacts with the dark energy field have been proposed as a solution to the cosmic coincidence problem, since in the attractor regime both dark energy and dark matter scale in the same way. In these models the mass of the cold dark matter particles is a function of the dark energy field responsible for the present acceleration of the Universe, and different scenarios can be parametrized by how the mass of the cold dark matter particles evolves with time. In this article we study the impact of a constant coupling $\ensuremath{\delta}$ between dark energy and dark matter on the determination of a redshift dependent dark energy equation of state ${w}_{\mathrm{DE}}(z)$ and on the dark matter density today from SNIa data. We derive an analytical expression for the luminosity distance in this case. In particular, we show that the presence of such a coupling increases the tension between the cosmic microwave background data from the analysis of the shift parameter in models with constant ${w}_{\mathrm{DE}}$ and SNIa data for realistic values of the present dark matter density fraction. Thus, an independent measurement of the present dark matter density can place constraints on models with interacting dark energy.

The Umami Chaplygin model

Relieve the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="d1e2446" altimg="si172.svg"><mml:msub><mml:mrow><mml:mi>H</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msub></mml:math> tension with a new coupled generalized three-form dark energy model

We study a modified interacting dark energy (MIDE) model as a candidate to describe possible interaction between dark energy and dark matter as well as that between dark energy and baryonic matter. More specifically, we introduce a new parameter γ b to quantify the extent of interaction between dark energy and baryons. With three classes of cosmological distance observations including CMB measurements from Planck and WMAP9 results, as well as the recent direct measurements of the Hubble parameter as a function of redshift, we study the allowable values of γ c and γ b and other cosmological parameters. The constraint results obtained by using the MCMC method show: (1) The interaction term γ b quantifying the extent of interaction between baryonic matter and dark energy is nearly equal to 0, which strongly support the whole coupled dark energy scenario based on the assumption that baryons should remain uncoupled in order to allow a non-negligible coupling to dark matter. (2) At the 95.4 % confidence level, we see the energy of dark energy is slightly transferring to that of dark matter; (3) Concerning the typical value of the present energy density ratio between baryonic matter and dark matter in the universe, we obtain a positive coupling between dark energy and matter at 2σ, which indicates that dark energy is leaking energy to matter. Finally, concerning the observational density parameter ratio Ω b /Ω m derived from the gas mass fraction data (f g a s ), within the framework of the phenomenological interaction model, we observe a good compatibility between the observational constraints from f g a s and other combined data.

We have considered a cosmological model of holographic dark energy interacting with dark matter and another unknown component of dark energy of the universe. We have assumed two interaction terms Q and Q′ in order to include the scenario in which the mutual interaction between the two principal components (i.e., holographic dark energy and dark matter) of the universe leads to some loss in other forms of cosmic constituents. Our model is valid for any sign of Q and Q′. If Q<Q′, then part of the dark energy density decays into dark matter and the rest in the other unknown energy density component. But if Q>Q′, then dark matter energy receives from dark energy and from the unknown component of dark energy. Observation suggests that dark energy decays into dark matter. Here we have presented a general prescription of a cosmological model of dark energy which imposes mutual interaction between holographic dark energy, dark matter and another fluid. We have obtained the equation of state for the holographic dark energy density which is interacting with dark matter and other unknown component of dark energy. Using first law of thermodynamics, we have obtained the entropies for holographic dark energy, dark matter and other component of dark energy, when holographic dark energy interacting with two fluids (i.e., dark matter and other component of dark energy). Also we have found the entropy at the horizon when the radius (L) of the event horizon measured on the sphere of the horizon. We have investigated the GSL of thermodynamics at the present time for the universe enveloped by this horizon. Finally, it has been obtained validity of GSL which implies some bounds on deceleration parameter q.

In this paper we study the consequences of relaxing the hypothesis of the pressureless nature of the dark matter component when determining constraints on dark energy. To this aim we consider simple generalized dark matter models with constant equation of state parameter. We find that present-day low-redshift probes (type-Ia supernovae and baryonic acoustic oscillations) lead to a complete degeneracy between the dark energy and the dark matter sectors. However, adding the cosmic microwave background (CMB) high-redshift probe restores constraints similar to those on the standard $\Lambda$CDM model. We then examine the anticipated constraints from the galaxy clustering probe of the future Euclid survey on the same class of models, using a Fisher forecast estimation. We show that the Euclid survey allows us to break the degeneracy between the dark sectors, although the constraints on dark energy are much weaker than with standard dark matter. The use of CMB in combination allows us to restore the high precision on the dark energy sector constraints.

In this paper, we investigate the possibility of testing the weakly interacting massive particle (WIMP) dark matter (DM) models by applying the simplest phenomenological model which introduces an interaction term between dark energy (DE) and WIMP DM, i.e., Q = 3γDMHρDM. In general, the coupling strength γDE is close to 0 as the interaction between DE and WIMP DM is very weak, thus the effect of γDE on the evolution of Y associated with DM energy density can be safely neglected. Meanwhile, our numerical calculation also indicates that xf ≈ 20 is associated with DM freeze-out temperature, which is the same as the vanishing interaction scenario. As for DM relic density, it will be magnified by frac{2-3{upgamma}_{mathrm{DM}}}{2}{left[2pi {g}_{ast }{m}_{mathrm{DM}}^3/left(45{s}_0{x}_f^3right)right]}^{gamma_{mathrm{DM}}} times, which provides a new way to test WIMP DM models. As an example, we analyze the case in which WIMP DM is a scalar DM. (SGL+SNe+Hz) and (CMB+BAO+SNe) cosmological observations will give γDM = {0.134}_{-0.069}^{+0.17} and γDM = −0.0008 ± 0.0016, respectively. After further considering the constraints from DM direct detection experiment, DM indirect detection experiment, and DM relic density, we find that the allowed parameter space of the scalar DM model will be completely excluded for the former cosmological observations, while it will increase for the latter ones. Those two cosmological observations lead to an almost paradoxical conclusion. Therefore, one could expect more stringent constraints on the WMIP DM models, with the accumulation of more accurate cosmological observations in the near future.

Robot-controlled optical fibers will help create 3D map of the cosmos.

Testing the interaction between dark energy and dark matter with H(z) data