相关论文: The need for dark matter in galaxies
We elaborate further the $\mu$-deformation-based approach to modeling dark matter, in addition to the earlier proposed use of $\mu$-deformed thermodynamics. Herein, we construct $\mu$-deformed analogs of the Lane-Emden equation (for density…
The missing of a Keplerian fall-off in the observed galaxy rotation curves represents classical evidence for the existence of dark matter on galactic scales. There has been some recent activity concerning the potential of modelling galactic…
We suggest a new explanation of flatness of galaxies rotation curves without invoking dark matter. For this purpose a new gravitational tensor field is introduced in addition to the metric tensor.
The missing gravity in galaxies requires dark matter, or alternatively a modification of gravity or inertia. These theoretical possibilities of fundamental importance may be distinguished by the statistical relation between the observed…
We continue our study of the application of the conformal gravity theory to galactic rotation curves. Previously we had studied a varied 111 spiral galaxy sample consisting of high surface brightness galaxies, low surface brightness…
A solution for the problem of understanding observed rotation curves in galaxies without the introduction of dark matter halos is presented. This solution has been obtained upon considering the distribution of masses in the expanding…
In this thesis, we investigate some aspects of dark matter phenomenology and its predictive power in explaining the flattening of galaxy rotation curves at large distances. After outlining the Standard Model of particle physics, its…
The dark matter hypothesis, which is not called into question here, explains why typical rotation curves of spiral galaxies do not follow a Keplerian profile. It is however not sufficient in itself to explain why the whole matter…
Higher order curvature gravity has recently received a lot of attention due to the fact that it gives rise to cosmological models which seem capable of solving dark energy and quintessence issues without using "ad hoc" scalar fields. In…
Previous studies of dwarf irregular galaxies have mostly found that these systems have slowly rising rotation curves and that they are dominated by dark matter, even well within the optical disk. However, based on new observations and a…
We consider the singular configurations of gravitating gas [1] which could be used as a model for disk galaxies. The simplest steady configuration, which corresponds to rotation of stars around center gives flat rotational curve, provided…
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 analyze the presence of an additional singular thin disk in the recent General Relativistic model of galactic gravitational field proposed by Cooperstock and Tieu. The physical variables of the disk's energy-momentum tensor are…
It was shown earlier by Rahaman et al. that a noncommutative-geometry background can account for galactic rotation curves without the need for dark matter. The smearing effect that characterizes noncommutative geometry is described by means…
The concept of dark matter in the Universe and its components has been discussed in the 1930s by several authors, and in particular by Oort (1932) and Zwicky (1933). However, it is only in the 1970s that the existence of dark matter was…
Unhappily, there has been a maelstrom of problems for dark matter theories over the last few years and many serious difficulties still have no resolution in sight. This article reviews the evidence for dark matter in galaxies. The haloes…
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.
Recent measurements of gas velocity in the outer parts of high redshift galaxies suggest that steeply falling rotation curves may be common, or even universal, in these galaxies, in contrast to the near universal flat, non-declining…
Modified Newtonian Dynamics (MOND) and its relativistic version - TeVeS offer us an alternative perspective to understand the universe without the demand of the elusive cold dark matter. This MONDian paradigm is not only competitive with…
We show that it is not possible in the absence of dark matter to construct a four-dimensional metric that explains galactic observations. In particular, by working with an effective potential it is shown that a metric which is constructed…