Related papers: General Relativistic Galaxy Rotation Curves: Impli…
It is now, generally, believed that the presence of some form of dark matter is essential to explain the flat rotation curves of galaxies, and anomalous large velocities of galaxies in the clusters and superclusters. This dark matter turns…
In the present investigation flat rotational curves of the galaxies are considered under the framework of brane-world models where the 4d effective Einstein equation has extra terms which arise from the embedding of the 3-brane in the $5d$…
One key piece of evidence for dark matter is the rotation-curve problem: the disagreement between measured galactic rotation curves and their luminous mass. A novel solution to this problem is presented here, in a model that predicts…
The Luminous Convolution Model (LCM) demonstrates that it is possible to predict the rotation curves of spiral galaxies directly from estimates of the luminous matter. We consider two frame-dependent effects on the light observed from other…
The late infall of dark matter onto a galaxy produces structure (such as caustics) in the distribution of dark matter in the halo. We argue that such structure is likely to occur generically on length scales proportional to $l \sim t_0…
The rotation curves of low surface brightness galaxies provide a unique data set with which to test alternative theories of gravitation over a large dynamic range in size, mass, surface density, and acceleration. Many clearly fail,…
The recent paper by Lee and Lee (2004) may strongly leave the impression that astronomers have established that the rotation curves of spiral galaxies are flat. We show that the old paradigm of Flat Rotation Curves lacks, today, any…
The strong proper time dilation and radial contraction in the gravitational field of compact sources leads to a frozen state of matter. It is shown that the falling particles and photons can not cross the gravitational radius due to the…
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…
In this work we study rotation curves of spiral galaxies using a model of dark matter based on a scalar-tensor theory of gravity. We show how to estimate the scalar field dark matter parameters using a sample of observed rotation curves.
We summarize our studies on the determination of the mass of the dark matter halo, based on observations of rotation curves of test particles or of the gravitational lensing. As we show, it is not uncommon that some studies on the nature of…
A new method is developed which permits the reconstruction of the surface-density distribution in the galactic disk of finite radius from an arbitrary smooth distribution of the angular velocity via two simple quadratures. The existence of…
Using high-accuracy rotation curves of spiral galaxies, we derive distributions of the surface mass density. Comparing with the luminosity profiles, we show that the dark mass in disk and bulge distributions follows those of luminous…
It is generally thought that galaxies are embedded in dark matter halos extending well beyond their luminous matter. The existence of these galactic halos is mainly derived from the larger than expected velocities of stars and gas in the…
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…
Gravitational lensing has now become a popular tool to measure the mass distribution of structures in the Universe on various scales. Here we focus on the study of galaxy's scale dark matter halos with galaxy-galaxy lensing techniques:…
Recent work on the mass distribution in spiral galaxies, using mainly HI observations, is reviewed. The principal problem is still to determine to what extent the dark matter is important in the inner parts of a galaxy, or in other words,…
We consider the possibility that the dark matter is coupled through its mass to a scalar field associated with the dark energy of the Universe. In order for such a field to play a role at the present cosmological distances, it must be…
The evidence of the phenomenon for which, in galaxies, the gravitating mass is distributed differently than the luminous mass, increases as new data become available. Furthermore, this discrepancy is well structured and it depends on the…
The standard cold dark matter (CDM) model has recently been challenged by the claim that dwarf galaxies have dark matter halos with constant density cores. Consequently, numerous alternative dark matter candidates have recently been…