Related papers: Galactic constraints on CHAMPs
We derive a complementary cosmological upper bound on the fraction of dark matter residing inside massive compact halo objects (MACHOs) using the cosmic dawn and dark ages global 21-cm signal $(T_{21})$. MACHOs of masses $M\gtrsim…
How much dark matter is there in the universe and where is it located? These are two of the most fundamental questions in cosmology. We use in this paper optical and x-ray mass determinations of galaxies, groups, and clusters of galaxies to…
A possible solution to the small scale problems of the cold dark matter (CDM) scenario is that the dark matter consists of two components, a cold and a warm one. We perform a set of high resolution simulations of the Milky Way halo varying…
We point out a new and largely model-independent constraint on the dark matter scattering cross section with nucleons, applying when this quantity is larger than for typical weakly interacting dark matter candidates. When the dark matter…
In the early 1990's, an analysis was completed by several theorists of the available mass/cross-section parameter space for unusual particle candidates to solve the dark matter problem, e.g. strongly interacting massive particles (SIMPs).…
The detection of stars in the process of being tidally removed from globular clusters and dwarf spheroidals in the Galaxy's halo provides a strong constraint on their mass to light ratios and on the extent of their possible dark matter…
Unhappily, there has been a maelstrom of problems for dark matter theories over the last few years and many serious difficulties still have no resolution in sight. This article reviews the evidence for dark matter in galaxies. The haloes…
Using the approach of autonomous Hamiltonian dynamical system, we attempt to estimate the as yet unknown upper limit on the size of the galactic halo surrounding galaxies (lenses). The key to determine the size of the halo is to determine…
Light scalar fields are expected to arise in theories of high energy physics (such as string theory), and find phenomenological motivations in dark energy, dark matter, or neutrino physics. However, the coupling of light scalar fields to…
Dark matter density is formally infinite at the location of caustic surfaces, where dark matter sheet folds in phase space. The caustics separate multi-stream regions with different number of streams. Volume elements change the parity by…
Several ideas for new physics beyond the standard model may provide particle candidates for the dark matter in the Galactic halo. The two leading candidates are an axion and a weakly-interacting massive particle (WIMP), such as the…
We present an update of results from the search for microlensing towards the Large Magellanic Cloud (LMC) by EROS (Experience de Recherche d'Objets Sombres). We have now monitored 25 million stars over three years. Because of the small…
The nature of the dark matter in the Halo of our Galaxy remains a mystery. Arguments are presented that the dark matter does not consist of ordinary stellar or substellar objects, i.e., the dark matter is not made of faint stars, brown…
We place limits on the mean density of the universe and the slope of the linear power spectrum around a megaparsec scale by comparing the universal mass function to the observed luminosity function. Numerical simulations suggest that the…
Dark matter annihilations in the Galactic halo inject relativistic electrons and positrons which in turn generate a synchrotron radiation when interacting with the galactic magnetic field. We calculate the synchrotron flux for various dark…
One of the major and widely known small scale problem with the Lambda CDM model of cosmology is the core-cusp problem. In this study we investigate whether this problem can be resolved using bar instabilities. We see that all the initial…
Galaxies in the nearby Universe, particularly dwarf systems, exhibit inner mass profiles of dark matter haloes that systematically depart from canonical cold dark matter expectations, signalling an interplay between baryonic feedback and…
In this paper we examine whether indirect detection constraints on dark matter associated with a non-thermal history may be significantly improved when accounting for the presence of galactic substructure in the form of dark matter spikes.…
We analyze the relationship between the mass of a spherical component and the minimum possible thickness of stable stellar disks. This relationship for real galaxies allows the lower limit on the dark halo mass to be estimated (the thinner…
We argue that any violent galactic winds following early epoch of star bursts would significantly weaken the potentials of galaxies, and leave lasting signatures such as a lowered dark halo density and preferentially radial/escaping orbits…