Related papers: Quintessential Haloes around Galaxies
We investigate a simple model for a galactic halo under the assumption that it is dominated by a dark matter component in the form of a Bose-Einstein condensate involving an ultra-light scalar particle. In particular we discuss the…
Based on a set of cosmological N-body simulations we analyze properties of the dark matter haloes (DM) in a galaxy mass range ($10^{11} - 10^{13} h^{-1}M_{\odot}$) in modified $\lcdm$ cosmology with additional dynamically screened scalar…
Distance measurements to type Ia supernovae (SNe Ia) indicate that the universe is accelerating and it is spatially flat. Otherwise, the rotation curves for galaxies or galaxy clusters reveal the existence of a dark matter component. Then,…
We suggest that the dark matter model based on Bose Einstein condensate or scalar field can resolve the apparently contradictory behaviors of dark matter in the Abell 520 and the Bullet cluster. During a collision of two galaxies in the…
A fine balance between dark and baryonic mass is observed in spiral galaxies. As the contribution of the baryons to the total rotation velocity increases, the contribution of the dark matter decreases by a compensating amount. This poses a…
Dark matter (DM) can consist of a scalar field so light that DM particles in the galactic halo are best described by classical waves. We investigate how these classical solutions are influenced by the presence of a non-rotating supermassive…
Numerical simulations show that a long-range scalar interaction in a single species of massive dark matter particles causes voids between the concentrations of large galaxies to be more nearly empty, suppresses accretion of intergalactic…
We present cosmological perturbation theory in neutrinos probe interacting dark-energy models, and calculate cosmic microwave background anisotropies and matter power spectrum. In these models, the evolution of the mass of neutrinos is…
Observations show that about the 20% of the Universe is composed by invisible (dark) matter (DM), for which many candidates have been proposed. In particular, the anomalous behavior of rotational curves of galaxies (i.e. the flattening at…
A stable neutralino $\chi_1^0$, assumed to be the lightest supersymmetric particle, is a favored particle physics candidate for the cosmological Dark Matter. We study co-annihilation of the lightest neutralino with the lighter scalar top…
In this article, we propose a new way to handle interactions between two scalar fields in the cosmological backdrop where one scalar field oscillates rapidly in the cosmological time scale while the other does not show any periodic behavior…
The two most popular candidates for dark energy, i.e. a cosmological constant and quintessence, are very difficult to distinguish observationally, mostly because the quintessence field does not have sizable fluctuations. We study a scalar…
Dark matter is obtained from a scalar field coupled conformally to gravitation; the scalar being a relict of Dirac's gauge function. This conformally coupled dark matter includes a gas of very light ($m\approx 2.25\times 10^{-34} eV$)…
The Short BaseLine (SBL) neutrino oscillation anomalies hint at the presence of a sterile neutrino with a mass of around 1 eV. However, such a neutrino is incompatible with cosmological data, in particular observations of the Cosmic…
Continuing with previous works, we present a cosmological model in which dark matter and dark energy are modeled by scalar fields $\Phi $ and $\Psi$, respectively, endowed with the scalar potentials $V(\Phi)=V_{o}[ \cosh {(\lambda…
The presence of unseen halos of ``dark matter'' has long been inferred from the high rotation speeds of gas and stars in the outer parts of spiral galaxies$^{1}$. The volume density of this dark matter decreases less quickly from the…
The existence of dark energy is essential to explain the cosmic accelerated expansion. We consider a homogenous interacting tachyonic scalar field as a possible candidate for the dynamical dark energy. The interaction between the tachyonic…
In the last time the cold dark matter (CDM) model has suggested more and more that it is not able to describe all the properties of nearby galaxies that can be observed in great detail as well as that it has some problems in the mechanism…
The present surge for the astrophysical relevance of boson stars stems from the speculative possibility that these compact objects could provide a considerable fraction of the non-baryonic part of dark matter within the halo of galaxies.…
In this paper we consider that dark energy could be described solely by a complex scalar field with a Bose-Einstein condensate-like potential (denoted as CSFDE), that is, with a self-interaction and a mass term. In particular, we analyse a…