Related papers: Universal Acceleration and Fuzzy Dark Matter
We review the notion of holographic dark energy and assess its significance in the light of the well documented cosmic acceleration at the present time. We next propose a model of holographic dark energy in which the infrared cutoff is set…
Ultra-compact dwarf galaxies (UCDs) are stellar systems with masses of around 10^7 to 10^8 Msun and half mass radii of 10-100 pc. They have some properties in common with massive globular clusters, however dynamical mass estimates have…
In this paper, we consider the hypothesis in which a species of ultra light bosonic dark matter (ULBDM) with mass $m_{B}\sim 10^{-22}$ eV could be the dominant dark matter (DM) in the Universe. As a first approach we work in the context of…
In the past years a wealth of observations has unraveled the structural properties of dark and luminous mass distribution in galaxies, a benchmark for understanding dark matter and the process of galaxy formation. The study of the…
The dark sector of the Universe need not be completely separable into distinct dark matter and dark energy components. We consider a model of early dark energy in which the dark energy mimics a dark matter component in both evolution and…
The process of diffusive acceleration of charged particles in shocked plasmas is widely invoked in astrophysics to account for the ubiquitous presence of signatures of non-thermal relativistic electrons and ions in the universe. A key…
From an observational perspective cosmology is today in excellent shape - advances in instrumentation and data processing have enabled us to study the universe in detail back to when the first galaxies formed, map the fluctuations in the…
In fuzzy dark matter (FDM) cosmologies, the dark matter consists of ultralight bosons ($m\lesssim10^{-20}$ eV). The astrophysically large de Broglie wavelengths of such particles hinder the formation of low-mass dark matter halos. This…
We suggest that two-to-two dark matter fusion may be the relaxation process that resolves the small-scale structure problems of the cold collisionless dark matter paradigm. In order for the fusion cross section to scale correctly across…
The cold dark matter spectrum on earth is expected to have peaks in velocity space. We obtain estimates for the sizes and locations of these peaks. To this end we have generalized the secondary infall model of galactic halo formation to…
Studies of galaxy surveys in the context of the cold dark matter paradigm have shown that the mass of the dark matter halo and the total stellar mass are coupled through a function that varies smoothly with mass. Their average ratio…
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…
We investigate several varying-mass dark-matter particle models in the framework of phantom cosmology. We examine whether there exist late-time cosmological solutions, corresponding to an accelerating universe and possessing dark energy and…
From the observed results of the space distribution of quasars we deduced that neutrino mass is about10^(-1) eV. The fourth stable elementary particle (delta particle) with mass about 10^(0) eV can help explain the energy resource mechanism…
Dark energy in the universe is assumed to be vacuum energy. The energy-momentum of vacuum is described by a scale-dependent cosmological constant. The equations of motion imply for the density of matter (dust) the sum of the usual matter…
In the present paper, it is found that dark energy emerges spontaneously from the modified gravity. According to cosmological scenario, obtained here, the universe inflates for $\sim 10^{-37}$ sec. in the beginning and late universe…
We find that an observer with a suitable acceleration relative to the frame comoving whit the cosmic fluid, in the context of the FRW decelerating universe, measures the same cosmological redshift as the LambdaCDM model. The estimated value…
We explore the cosmology of the Dark Dimension scenario taking into account perturbations in the linear regime. In the context of the Dark Dimension scenario, a natural candidate for dark matter in our universe is the excitations of a tower…
Most of the mass of ordinary matter has its origin from quantum chromodynamics (QCD). A similar strong dynamics, dark QCD, could exist to explain the mass origin of dark matter. Using infrared fixed points of the two gauge couplings, we…
We consider a simple class of models in which the dark matter, X, is coupled to a new gauge boson, phi, with a relatively low mass (m_phi \sim 100 MeV-3 GeV). Neither the dark matter nor the new gauge boson have tree-level couplings to the…