Related papers: Neutrinos as cluster dark matter
Measurements of the evolution with redshift of the number density of massive galaxy clusters are used to constrain the energy density of massive neutrinos and so the sum of neutrino masses $\sum m_\nu$. We consider a spatially-flat…
Assuming that there exists a species of heavy sterile neutrinos($m_{\nu}>1$ keV) and their decays can serve as a heating source of the hot gas in galaxy clusters, we study how the observational constraints on cooling flow limit the mass of…
Neutrinos are produced in several neutrino nuclear reactions of the proton-proton chain and carbon-nitrogen-oxygen cycle that take place at different radius of the Sun's core. Hence, measurements of solar neutrino fluxes provide a precise…
The largest clusters of galaxies in the Universe contain vast amounts of dark matter, plus baryonic matter in two principal phases, a majority hot gas component and a minority cold stellar phase comprising stars, compact objects, and…
We propose a simple and flexible mechanism by which sterile neutrinos with masses below the electroweak scale can simultaneously account for the observed baryon asymmetry of the Universe and the dark matter abundance. Crucially, neutrinos…
To further test MOdified Newtonian Dynamics (MOND) on galactic scales -- originally proposed to explain the rotation curves of disk galaxies without dark matter -- we study a sample of six strong gravitational lensing early-type galaxies…
The large scale structure of the present Universe is determined by the growth of dark matter density fluctuations and by the dynamical action of dark energy and dark matter. While much progress has been made in recent years in constraining…
We present the analysis of 23 published rotation curves of disk galaxies belonging to the Ursa Major group of galaxies, with kinematics free of irregularities. The rotation curves are analysed in the context of MOND (Modified Newtonian…
New, high resolution, large-scale, cosmological hydrodynamic galaxy formation simulations of a standard cold dark matter model (with a cosmological constant) are utilized to predict the distribution of baryons at the present and at moderate…
The recent observational evidence for the current cosmic acceleration have stimulated renewed interest in alternative cosmologies, such as scenarios with interaction in the dark sector (dark matter and dark energy). In general, such models…
Observations of galaxies suggest a one-to-one analytic relation between the inferred gravity of dark matter at any radius and the enclosed baryonic mass, a relation summarized by Milgrom's law of modified Newtonian dynamics (MOND). However,…
We propose a new cosmological test of gravity, by using the observed mass fraction of X-ray emitting gas in massive galaxy clusters. The cluster gas fraction, believed to be a fair sample of the average baryon fraction in the Universe, is a…
One of the most important problems in astrophysics concerns the nature of the dark matter in galactic halos, whose presence is implied mainly by the observed flat rotation curves in spiral galaxies. Due to the Pauli exclusion principle it…
Non-baryonic Dark Matter (DM) appears in galaxies and other cosmic structures when and only when the acceleration of gravity, as computed considering only baryons, goes below a well defined value a0=1.2e-8 cm/s/s. This might indicate a…
A wealth of astronomical data indicate the presence of mass discrepancies in the Universe. The motions observed in a variety of classes of extragalactic systems exceed what can be explained by the mass visible in stars and gas. Either (i)…
The small-scale power spectrum of the cosmological matter distribution together with other cosmological data provides a sensitive measure of the hot dark matter fraction, leading to restrictive neutrino mass limits. We extend this argument…
We present results from the analysis of cosmic microwave background (CMB), large scale structure (galaxy redshift survey) and X-ray galaxy cluster (baryon fraction and X-ray luminosity function) data, assuming a geometrically flat…
Davidsen et al. (1991) have argued that the failure to detect uv photons from the dark matter DM) in cluster A665 excludes the decaying neutrino hypothesis. Sciama et al. (1993) argued that because of high central concentration the DM in…
Several lines of evidence suggest that cold, dense gas clouds make a substantial contribution to the total mass of dark halos. If so then physical collisions between clouds must occur; these cause strong, radiative shocks to propagate…
A specific modification of Newtonian dynamics known as MOND has been shown to reproduce the dynamics of most astrophysical systems at different scales without invoking non-baryonic dark matter (DM). There is, however, a long-standing…