Related papers: Constraining the dark energy with galaxy clusters …
We consider cosmological tests of a scalar-vector-tensor gravitational model, in which the dark energy is included in the total action through a gauge invariant, electromagnetic type contribution. The ground state of dark energy,…
We introduce a simple parametrization of the dark energy equation of state, \omega, which is motivated from theory and recent experimental data. The theory is related to the tracker solution to alleviate the fine tuning problem. Recent…
As experimentalists step up their pursuit of cold dark matter particles and neutrino masses, cosmological constraints are tightening. We compute the joint constraints on 11 cosmological parameters from cosmic microwave background and large…
Some recent observations provide $> 2\sigma$ evidence for phantom dark energy -- a value of the dark energy equation of state less than the cosmological-constant value of $-1$. We focus on constraining the equation of state by combining…
In axion quintessence, the cosmological era with an energy contrast in dark energy 0.1 < Omega_DE < 0.9 may represent a significant fraction of the universe's lifetime if the minimum of the axion potential is negative (unstable axion…
We use the Riess et al.(2004) supernova Ia apparent magnitude versus redshift data and the Allen et al.(2004) galaxy cluster gas mass fraction versus redshift data to constrain dark energy models. These data provide complementary…
Late-time cosmic acceleration is one of the most interesting unsolved puzzles in modern cosmology. The explanation most accepted nowadays, dark energy, raises questions about its own nature, e.g. what exactly is dark energy, and…
The abundance of rich clusters is a strong constraint on the mass power spectrum. The current constraint can be expressed in the form $\sigma_8 \Omega_m^{\gamma} = 0.5 \pm 0.1$ where $\sigma_8$ is the $rms$ mass fluctuation on 8 $h^{-1}$…
We examine the dark energy and matter densities allowed by precision measurements of distances out to various redshifts, in the presence of spatial curvature and (near) arbitrary behavior of the dark energy equation of state. Degeneracies…
In this work, we quantify the cosmological signatures of dark energy radiation -- a novel description of dark energy, which proposes that the dynamical component of dark energy is comprised of a thermal bath of relativistic particles…
We review the ability of redshift surveys to provide constraints on the Dark Energy content of the Universe. The matter power spectrum and dynamics at the present epoch are nearly `blind' to Dark Energy, but combined with the CMB they can…
The combination of multiple observational probes has long been advocated as a powerful technique to constrain cosmological parameters, in particular dark energy. The Dark Energy Survey has measured 207 spectroscopically--confirmed Type Ia…
We propose to use alternative cosmic tracers to measure the dark energy equation of state and the matter content of the Universe [w(z) & \Omega_m]. Our proposed method consists of two components: (a) tracing the Hubble relation using…
Physics invites the idea that space contains energy whose gravitational effect approximates that of Einstein's cosmological constant, Lambda; nowadays the concept is termed dark energy or quintessence. Physics also suggests the dark energy…
We combine recent measurements of Cosmic Microwave Background Anisotropies, Supernovae luminosity distances and Baryonic Acoustic Oscillations to derive constraints on the dark energy equation of state w in the redshift range 0<z<2, using a…
Models in which dark energy interacts with dark matter have been proposed in the literature to help explain why dark energy should only come to dominate in recent times. In this paper, we present a dynamical framework to calculate…
We propose and implement a novel test to assess deviations from well-established concordance $\Lambda$CDM cosmology while inferring dark energy properties. In contrast to the commonly implemented parametric forms of the dark energy…
The presence of dark energy in the Universe is inferred directly from the accelerated expansion of the Universe, and indirectly, from measurements of cosmic microwave background (CMB) anisotropy. Dark energy contributes about 2/3 of the…
We present precise measurements of the X-ray gas mass fraction for a sample of luminous, relatively relaxed clusters of galaxies observed with the Chandra Observatory, for which independent confirmation of the mass results is available from…
The current concordance model of cosmology is dominated by two mysterious ingredients: dark matter and dark energy. In this paper, we explore the possibility that, in fact, there exist two dark-energy components: the cosmological constant…