Related papers: Flat Circular Velocities on a megaparsec scale fro…
We use a compilation of disc galaxy rotation curves to assess the role of the luminous component ("baryons") in the rotation curve diversity problem. As in earlier work, we find that rotation curve shape correlates with baryonic surface…
A recent study shows that gravitational scattering of dark matter, in the form of massive objects with mass $m \sim 10^3-10^4M_{\odot}$, could provide a possible solution to alleviate the small-scale structure problems of cold dark matter.…
It has been demonstrated that the difference between the Renormalised Brane World (RBW) model and the Lambda Cold Dark Matter ($\Lambda$CDM) model occurs only at sufficiently distant times. In this paper, it is shown that for spherically…
Two well studied dwarf galaxies -- NGC 3109 and NGC 6822 -- present some of the strongest observational support for a flat core at the center of galactic dark matter (DM) halos. We use detailed cosmologically motivated numerical models to…
We explore the possibility that the density profiles of elliptical galaxies and cold dark matter (CDM) halos found in cosmological simulations can be understood in terms of the same physical process, collisionless gravitational collapse. To…
Cosmological N--body simulations have revealed a remarkable similarity in the structure of dark matter halos formed in hierarchically clustering universes. Regardless of halo mass, cosmological parameters, and power spectrum of initial…
The spacetime satisfying the flat curve condition for galaxies is shown to be the zero mass limit of the dilaton blackhole with an exponential potential. We derive the geodesic equations and by studying rotational curves and light…
Weak gravitational lensing has become an important tool to study the properties of dark matter halos around galaxies, thanks to the advent of large panoramic cameras on 4m class telescopes. This area of research has been developing rapidly…
We use a set of cosmological N-body simulations to investigate the structural shape of galaxy-sized cold dark matter (CDM) halos. Unlike most previous work on the subject - which dealt with shapes as measured by the inertia tensor - we…
We present high-accuracy rotation curves, which show a steep nuclear rise and high-velocity central rotation, followed by a broad maximum in the disk and flat part. We use the rotation curves to directly calculate the radial distribution of…
Galactic rotation curves are a fundamental constraint for any cosmological model. We use controlled N-body simulations of galaxies to study the gravitational effect of baryons in a scenario with collisionless cold dark matter (CDM) versus…
Current explanation of the overabundance of dark matter subhalos in the Local Group (LG) indicates that there maybe a limit on mass of a halo, which can host a galaxy. This idea can be tested using voids in the distribution of galaxies: at…
We consider dark masses measured from kinematic tracers at discrete radii in galaxies for which baryonic contributions to overall potentials are either subtracted or negligible. Recent work indicates that rotation curves due to dark matter…
Galaxy surveys have shown that luminous galaxies are mainly distributed in large filaments and galaxy clusters. The remaining large volumes are virtually devoid of luminous galaxies. This is in concordance with the formation of the…
We present the results of a study of the average mass profile around galaxies using weak gravitational lensing. We use 45.5 deg^2 of R_C band imaging data from the Red-Sequence Cluster Survey (RCS) and define a sample of 1.2\times 10^5…
We propose a simple geometrical mechanism for the flattening of galactic rotation curves, the local compression of field lines around their planes induced either by the presence of thin string-like objects at the centers of galaxies or by…
Warm Dark Matter (WDM) has been invoked to resolve apparent conflicts of Cold Dark Matter (CDM) models with observations on subgalactic scales. In this work we provide a new and independent lower limit for the WDM particle mass (e.g.…
The circular velocity function (CVF) of galaxies is a fundamental test of the $\Lambda$ Cold Dark Matter (CDM) paradigm as it traces the variation of galaxy number densities with circular velocity ($v_{\rm{circ}}$), a proxy for dynamical…
Cosmological $N$-body simulations predict dark matter (DM) haloes with steep central cusps (e.g. NFW, Navarro et al. 1996). This contradicts observations of gas kinematics in low-mass galaxies that imply the existence of shallow DM cores.…
Models for DM are invoked with various density distributions, to account for flat rotation curves of galaxies. The effect of DE on these profiles for large galaxies and clusters are also studied. The rotation curves are shown to dip at a…