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From cosmic deceleration to acceleration: new constraints from SN Ia and BAO/CMB
We use type Ia supernovae (SN Ia) data in combination with recent baryonic acoustic oscillations (BAO) and cosmic microwave background (CMB) observations to constrain a kink-like parametrization of
Cosmological constraints from lensing statistics and supernovae on the cosmic equation of state
We investigate observational constraints from lensing statistics and high-z type Ia supernovae on flat cosmological models with nonrelativistic matter and an exotic fluid with an equation of state,
The end of unified dark matter
Despite the interest in dark matter and dark energy, it has never been shown that they are in fact two separate substances. We provide the first strong evidence that they are separate by ruling out a
Dark Interactions and Cosmological Fine-Tuning
Cosmological models involving an interaction between dark matter and dark energy have been proposed in order to solve the so-called coincidence problem. Different forms of coupling have been studied,
Decaying A cosmologies and statistical properties of gravitational lenses
In this paper we investigate the statistical properties of gravitational lenses for models in which a cosmological term decreases with time as $\Lambda \propto a^{-m}$, where $a$ is the scale factor
Constraining the cosmic deceleration-acceleration transition with type Ia supernova, BAO/CMB and H(z) data
We revisit the kink-like parametrization of the deceleration parameter (q(z)) [1], which considers a transition, at redshift zt, from cosmic deceleration to acceleration. In this parametrization the
Observational Constraints on Chaplygin Quartessence: Background Results
We derive the constraints set by several experiments on the quartessence Chaplygin model (QCM). In this scenario, a single fluid component drives the Universe from a nonrelativistic matter-dominated
Viable singularity-free f(R) gravity without a cosmological constant.
A particular two-parameter f(R) model is presented that is cosmologically viable and distinguishable from LambdaCDM, is compatible with the existence of relativistic stars, is free of singularities of the Ricci scalar during the cosmological evolution, and allows the addition of high-curvature corrections that could be relevant for inflation.