Related papers: A constant dark matter halo surface density in gal…
We re-examine the disk-halo decompositions of the rotation curves of low surface brightness (LSB) galaxies with V_max > 80 km/s, taking full account of the effects of beam smearing. We show that the rotation curves of these LSB galaxies…
We use the concept of the spiral rotation curves universality to investigate the luminous and dark matter properties of the dwarf disc galaxies in the local volume (size $\sim11$ Mpc). Our sample includes 36 objects with rotation curves…
We present Halpha rotation curves for a sample of 15 dwarf and LSB galaxies. From these, we derive limits on the slopes of the central mass distributions. Assuming the density distributions of dark matter halos follow a power-law at small…
A large number of studies have found that the dark matter surface density, given by the product of the dark matter core radius ($r_c$) and core density ($\rho_c$) is approximately constant for a wide range of galaxy systems. However, there…
Observations show that the underlying rotation curves at intermediate radii in spiral and low-surface brightness galaxies are nearly universal. Further, in these same galaxies, the product of the central density and the core radius…
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…
In this paper, we study the dynamical stability and time evolution of the central dark matter cores of low-mass (about 10^8-10^9 M_solar) galactic haloes found in recent cold dark matter simulations at high redshift. From those simulations…
High-quality optical rotation curves for a sample of low-luminosity spirals evidence that the dark halos around galaxies are inconsistent with the output of proper CDM simulations. In fact, dark halos enveloping stellar disks are structures…
The results obtained from a study of the mass distribution of 36 spiral galaxies are presented. The galaxies were observed using Fabry-Perot interferometry as part of the GHASP survey. The main aim of obtaining high resolution H alpha 2D…
A large number of observations have shown that the dark matter halo surface density, given by the product of halo core radius and core density is nearly constant for a diverse suite of galaxies. Although this invariance of the halo surface…
We combine observed properties of galaxies as the core density and radius with the theoretical linear evolution of density fluctuations computed from first principles since the end of inflation till today. The halo radius r_0 is computed in…
We investigate the clustering and dark matter halo mass for a sample of $\sim$16,000 central galaxies selected from the SDSS/DR7 group catalog. We select subsamples of central galaxies on three two-dimensional planes, each formed by stellar…
Recent observations indicate that dark matter haloes have flat central density profiles. Cosmological simulations with non-baryonic dark matter predict however self similar haloes with central density cusps. This contradiction has lead to…
From the kinematics of 137 spirals we find that the DM halo density profiles are self-similar at least out to R_opt and show core radii much larger that the corresponding disk scale-lenghts. The luminous regions of spirals consist of…
The relationship between galaxies and dark matter can be characterized by the halo mass of the central galaxy and the fraction of galaxies that are satellites. Here we present observational constraints from the SDSS on these quantities as a…
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…
Collisionless particles, such as cold dark matter, interact only by gravity and do not have any associated length scale, therefore the dark halos of galaxies should have negligible core radii. This expectation has been supported by…
We use N-body simulations to investigate the structure of dark halos in the standard Cold Dark Matter cosmogony. Halos are excised from simulations of cosmologically representative regions and are resimulated individually at high…
This study presents the mass distribution for a sample of 18 late-type galaxies in nine Hickson Compact Groups. We used rotation curves from high resolution 2D velocity fields of Fabry-Perot observations and J-band photometry from the 2MASS…
The distribution of dark matter around galactic or cluster halos has usually been assumed to be approximately isothermal with a non-zero core radius, which is expected to be of the order of the size of the visible matter distribution.…