The richness of tidal features seen in interacting galaxies allows for the determination of their characteristic parameters, provided one can deal with the extended parameter space. Genetic algorithm based methods – like our code minga – have proven to be such a tool. Here I discuss the implementation of dark matter halo descriptions in the restricted N-body simulations of minga. I show that the final morphology of a galaxy encounter strongly depends on the halo properties. Thus, modeling tidal features of interacting galaxies might allow also for conclusions on the galactic dark matter content.

We investigate the effect of the inhomogeneity of the background distribution on dynamical friction. We find a generalised Coulomb logarithm with position dependent maximum impact parameter scaling with the local scale length, which is usually much smaller than the distance to the centre of the background system. We apply the new formula to N-body calculations of satellite galaxies in Dark Matter haloes and find a systematic improvement of the orbit fits. Additionally a first order force not parallel to the motion of the massive object appears, which can be neglected at least in spherical systems due to the lack of a secular effect.

Cold Dark Matter with a large cosmological constant (ACDM) appears to fit large scale structure observations well. of the possible small scale problems, the Central Cusps and Too Many Satellites problems now appear to be at least partly solved, so Angular Momentum has become the most serious remaining CDM problem. There are actually at least two different angular momentum problems: A. Too much transfer of angular momentum to the dark halo to make big disks, and B. Wrong distribution of specific angular momentum to make spiral galaxies, if the baryonic material has the same angular momentum distribution as the dark matter. the angular momentum of dark matter halos, and presumably that of the galaxies they host, appears to arise largely from the orbital angular momentum of the satellites that they accrete. Since the dark and baryonic matter behave very differently in such accretion events, it is possible that the resulting angular momentum distribution of the baryons is different from that of the dark matter, as required to make the sort of galactic disks that are observed. the latest hydrodynamical simulations give some grounds for hope on this score, but much higher resolution simulations are needed.

We have performed high resolution cosmological N-body simulations in which halos of 1011 M⊙ are resolved with over 700 particles. We report on the internal structure of group-sized halos (masses between 1011M⊙ and 1014 M⊙), particularly on how the angular momentum within the halo correlates with the shape of the halo and with the angular momentum at other radii. We find that many halos have an inner region whose angular momentum is disconnected with that of the outer halo.

We discuss the possibility that angular momenta of galaxy structures are due to the global rotation of the Universe.

Weakly Interacting Massive Particle (WIMP) direct detection experiments are just reaching the sensitivity required to detect Galactic dark matter in the form of neutralinos (or indeed any stable weakly interacting particle). Detection strategies and data analyses are often based on the simplifying assumption of a standard spherical, isothermal halo model, but observations and numerical simulations indicate that galaxy halos are in fact triaxial and anisotropic, and contain substructure. the annual modulation and direction dependence of the event rate (due to the motion of the Earth) provide the best prospects of distinguishing WIMP scattering from background events, however these signals depend sensitively on the local WIMP velocity distribution. I briefly review the status of WIMP direct detection experiments before discussing the dependence of the annual modulation signal on astrophysical input, in particular the structure of the Milky Way halo, and the possibility that the local WIMP distribution is not smooth.

Neutralinos arise as natural cold dark matter candidates in many supersymmetric extensions of the Standard Model of particle physics. If Galactic neutralinos exist, they could in principle be detected by both direct and indirect detection techniques. We use the DarkSUSY package to make very accurate calculations of the expected detection rates for a wide scan of parameter values. We compare the calculations with the sensitivity of current and future detectors, and conclude that some of the models are above the sensitivity limits. Comments are also made on the mutual dependence between the halo profile and the detection rates.

CRESST II is an experiment for direct WIMP search, using cryogenic detectors. the ratio of the two signals (temperature rise and scintillation light) measured for each interaction is an excellent parameter for discrimination of the radioactive background. the main remaining background is the neutron flux present at the experimental site, since neutrons produce the same signals as WIMPs do. Based on Monte Carlo simulations the present work shows how neutrons from different origins affect CRESST and which measures have to be taken into account to reach the sensitivity goal.

The CRESST experiment is set up for the direct detection of Weakly Interacting Massive Particles (WIMPs) which our Galactic dark matter halo possibly consists of. the employed detection method is elastic scattering by nuclei. the recoiling nucleus deposits most of its energy in the form of lattice vibrations in the detector. Cooling the detector to very low temperatures (mK) enhances the temperature rise due to the energy deposition. the crucial parameter for direct WIMP searches is the sensitivity to the WIMP interaction cross section in a certain range of possible WIMP masses. CRESST is now sensitive enough to explore the parameter space predicted by supersymmetric models.

The status of the dark matter search program at the Boulby Underground Laboratory is reviewed. Recent results are presented and plans for future generation experiments are discussed.

Certain solutions to a gravitational form of Schrödinger's equation can yield stable, macroscopic eigenstate solutions having no classical analogue, with properties resembling those of dark matter. Some more tractable solutions show: (1) radiative lifetimes far exceeding the universe's age, implying negligible emission and inherent stability w.r.t. gravitational collapse, (2) negligible interaction with EMR and visible matter, (3) potential to give rise to flat rotation curves and (4) eigenstate energies and “sizes” consistent with that expected for the galactic halo. Traditional baryonic particles occupying such eigenstates will be invisible and weakly interacting, and may be assimilated into galactic evolution scenarios without significantly disturbing BBN ratios. It is proposed that such structures may explain the nature and origin of dark matter.