Related papers: Dark energy: investigation and modeling
Recent cosmological observations suggest that nearly seventy per cent of the energy density in the universe is unclustered and has negative pressure. Several conceptual issues related to the modeling of this component (`dark energy'), which…
The presence of dark energy in the Universe is inferred directly and indirectly from a large body of observational evidence. The simplest and most theoretically appealing possibility is the vacuum energy density (cosmological constant).…
In the standard model of cosmology, dark matter and dark energy are presently the two main contributors to the total energy in the Universe. However, these two dark components are still of unknown nature, and many alternative explanations…
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…
Taking up four model universes we study the behaviour and contribution of dark energy to the accelerated expansion of the universe, in the modified scale covariant theory of gravitation. Here, it is seen that though this modified theory may…
To explain the currently observed accelerated expansion of the universe, a large number of different theoretical models are presently being discussed. In one way or another, all of these contain `new physics', though at different levels.…
The idea of a negative-pressure dark energy component in the Universe which causes an accelerated expansion in the late Universe has deep implications in models of field theory and general relativity. In this article, we survey the evidence…
A huge amount of good quality astrophysical data converges towards the picture of a spatially flat universe undergoing the today observed phase of accelerated expansion. This new observational trend is commonly addressed as Precision…
The origin of the dark energy which is assumed to be responsible for the observed accelerated expansion of the universe still remains a scientific dilemma. Here we propose a tentative origin for this energy, if it is coming from a…
Type Ia supernovae are a powerful cosmological probe, that gave the first strong evidence that the expansion of the universe is accelerating. Here we provide an overview of how supernovae can go further to reveal information about what is…
The current expansion of the Universe has been observed to be accelerating, and the widely accepted spatially-flat concordance model of general relativistic cosmology attributes this phenomenon to a constant dark energy, a cosmological…
Measurements suggest that our universe has a substantial dark energy component. The most recent data on type Ia supernovae give a dark energy density which is in good agreement with other measurements if the dark energy is assumed to be a…
A large number of recent observational data strongly suggest that we live in a flat, accelerating Universe composed of $\sim$ 1/3 of matter (baryonic + dark) and $\sim$ 2/3 of an exotic component with large negative pressure, usually named…
The discovery that we live in an accelerating universe changed drastically the paradigm of physics and introduced the concept of \textit{dark energy}. In this work, we present a brief historical description of the main events related to the…
Observations suggest that nearly seventy per cent of the energy density in the universe is unclustered and exerts negative pressure. Theoretical understanding of this component (`dark energy'), which is driving an accelerated expansion of…
The expansion of the universe has been accepted by scientists for more than a century. However, since the 1990s, observations have suggested that the universe is expanding at an accelerating rate. Although the source of this acceleration is…
The recently observed accelerated expansion of the universe has put a challenge for its theoretical understanding. As a possible explanation of this, it is considered that the most part of the present universe is filled with a form of…
We present a complete analysis of the observational constraints and cosmological implications of our Bound Dark Energy (BDE) model aimed to explain the late-time cosmic acceleration of the universe. BDE is derived from particle physics and…
The currently available cosmological data yield, as a most striking result, that the expansion rate of the universe seems to be increasing at late times, contrary to the standard (zero cosmological constant) FLRW prediction. The usual…
This review considers the theoretical approaches to the understanding of dark energy which comprises approximately 68\% of the energy of our Universe and explains an acceleration in its expansion. Following a discussion of the main approach…