In the north-western Himalaya, the distribution of modem glaciers and snowlines in the Ladakh and Zanskar Ranges adjacent to the Indus River valley suggests comparable climatic conditions prevail in the two ranges. Similarly, the positions of terminal moraines and reconstructed equilibrium-line altitudes (ELAs) indicate equivalent magnitudes of Neoglacial and Late Glacial advances in both ranges. However, the terminal positions and reconstructed ELAs from the late Pleistocene maximum advances are at least 400 m lower in the Ladakh Range than in the nearby Zanskar Range. These differences do not appear to reflect either climatic or tectonic controls. Rather, they are caused by an unusual bedrock configuration in the Zanskar Range, where vertical strata of indurated sandstones and conglomerates, and narrow steep-walled canyons cut through them, created a bulwark that effectively precluded significant down-valley advance. Without recognition of this physical impedance to glacial advance, uncritical reconstructions would greatly overestimate the altitude of the ELA in the Zanskar Range.

An N-map Iterated Fuzzy Set System (IFZS), introduced in [4] and to be denoted as (w, Φ), is a system of N contraction maps wi: X → X over a compact metric space (X, d), with associated “grey level” maps øi: [0, 1] → [0, 1]. Associated with an IFZS (w, Φ) is a fixed point u ∈ f*(X), the class of normalized fuzzy sets on X, u: X → [0, 1]. We are concerned with the continuity properties of u with respect to changes in the wi, and the φi. Establishing continuity for the fixed points of IFZS is more complicated than for traditional Iterated Function Systems (IFS) with probabilities since a composition of functions is involved. Continuity at each specific attractor u may be established over a suitably restricted domain of φi maps. Two applications are (i) animation of images and (ii) the inverse problem of fractal construction.

We have studied the structural and dynamical parameters of two samples of elliptical-like-objects (ELOs)formed in a set of self-consistent hydrodynamical simulations.ELO stellar masses,projected half- stellar mass radii, and stellar centrall.o.s. velocity dispersions have been found to define a dynamical Fundamental Plane (FP), whose physical origin we report on.

From a sample of more than 100 remnants from major and minor hydrodynamic binary galaxy merger simulations (Cox 2004; Cox et al. 2005), we find that stellar remnants are mostly oblate while dark matter halos are mostly prolate or triaxial. Shapes are determined by iteratively diagonalizing a moment-of-inertia tensor. The preferred axes of the two shapes are almost always nearly perpendicular. This can be understood by considering the influence of angular momentum and dissipation during the merger. If binary major mergers of spiral galaxies are responsible for the formation of elliptical galaxies or some subpopulation of elliptical galaxies, then the galaxies can be be expected to be oblate and the dark matter halos prolate with the two preferred axes perpendicular to each other.

We present high resolution two dimensional velocity fieldsfrom integral field spectroscopy along with derived rotation curves for nine low surface brightness galaxies. This is a positive step forward in terms of both data quality and number of objects studied. We fit NFW and pseudo-isothermal halo models to the observations. We find that the pseudo-isothermal halo better represents the data in most cases than the NFW halo, as the resulting concentrations are lower than would be expected for ΛCDM.

The nonperturbative renormalization group flow of Quantum Einstein Gravity (QEG) is reviewed. It is argued that there could be strong renormalization effects at large distances, in particular a scale dependent Newton constant, which mimic the presence of dark matter at galactic and cosmological scales.

The standard model of cosmology considers the existence of two components of unknown nature, “dark matter” and “dark energy”, which determine the cosmological evolution. Their nature remains unknown, and other models can also be considered. In particular, it may be possible to reinterpret the recent cosmological observations so that the Universe does not contain two fluids of unknown natures, but only one fluid with particular properties. After a brief review of constraints on this unifying “dark fluid”, we will discuss a specific model of dark fluid based on a complex scalar fluid.

One can solve the Jeans equation analytically forequilibrated dark matter structures, once given two pieces of inputfrom numerical simulations. These inputs are 1) a connection betweenphase-space density and radius, and 2) a connection between velocityanisotropy and density slope, the α – β relation. The first(phase-space density vs. radius) has been analysed through severaldifferent simulations, however the second (α – β relation) has notbeen quantified yet. We perform a large set of numerical experimentsin order to quantify the slope and zero-point of the α – βrelation. This allows us to conclude that equilibrated dark matterstructures indeed have zero central velocity anisotropy,central densityslope of α0 ≈ –0.8, and outer anisotropy ofapproximately β∞ ≈ 0.5.

Cosmological simulations of structure formation predict that galaxiesare dramatically modified by galaxy harassment during the assembly ofgalaxy clusters, losing a substantial fraction of their stellar masswhich today must be in the form of intracluster stars. Simulationspredict non-uniform spatial and radial velocity distributions forthese stars. Intracluster planetary nebulae are the only abundantcomponent of the intracluster light whose kinematics can be measuredat this time. Comparing these velocity distributions with simulationswill provide a unique opportunity to investigate the hierarchicalcluster formation process as it takes place in the nearby universe.

We present HI data of the dwarf galaxy DDO 47, aimed at testingthe hypothesis that dark halo triaxiality might induce non-circular motions resultingin rotation curves best fitted by cored halos, even if the dark matter halo is intrinsicallycuspy. We performed a harmonic decomposition of the velocity field in order to search for alleged non-circular motions needed to “hide” a cusp: in DDO 47non-circular motions are globally at a level of 2–3 km s-1, far from being sufficient to reconcile the observed rotation curvewith the ΛCDM predictions.We conclude that the dark matter halo around DDO 47 is truly cored and that a cusp cannot be hidden by non-circular motions.More details are shown in Gentile et al. (2005).

We use the mass-to-light gradients in early-type galaxies to infer the global dark matter fraction, fd = Md/M*, for these systems. We discuss implications about the total star formation efficiency in dark-matter halos and show that the the trend of fd with mass produces virial mass-to-light ratios which are consistent semi-analitical models. Preliminary kurtosis analysis of the quasi-constant M/L galaxies in Romanowsky et al. seems at odd with Dekel et al. simulations.

The mass distribution of galaxy clusters can be determined from thestudy of the projected phase-space distribution of cluster galaxies.The main advantage of this method as compared to others, is that itallows determination of cluster mass profiles out to very largeradii. Here I review recent analyses and results on this topic. Inparticular, I briefly describe the Jeans and Caustic methods, and theproblems one has to face in applying these methods to galaxysystems. Then, I summarize the most recent and important results onthe mass distributions of galaxy groups, clusters, and superclusters.Additional covered topics are the relative distributions of the darkand baryonic components, and the orbits of galaxies in clusters.

Polar ring galaxies, where matter is in equilibrium in perpendicularorbits around spiral galaxies, are ideal objects to probe the 3D shapesof dark matter halos. The conditions to constrain the halos are that theperpendicular system does not strongly perturb the host galaxy, or thatit is possible to derive back its initial shape, knowing the formationscenario of the polar ring. The formation mechanisms are reviewed:mergers, tidal accretion, or gas accretion from cosmic filaments.The Tully-Fisher diagram for polar rings reveals that the velocityin the polar plane is higher than in the host plane, which can only be explained if the dark matter is oblate and flattened along the polar plane. Only a few individual systems havebeen studied in details, and 3D shapes of their haloes determinedby several methods. The high frequency of warps could be explainedby spontaneous bending instability, if the disks are sufficientlyself-gravitating, which can put constraints on the dark matter flattening.


Recent X-ray observations have been showing that the old vision ofclusters as peacefully relaxed structures is in most cases absolutelywrong. Coupled with optical and radio observations, these X-ray datashow evidence for violent mechanisms. Results based on XMM-Newton gastemperature maps for four clusters will be presented here.