General Relativistic Galaxy Rotation Curves: Implications for Dark Matter Distribution

Dark matter has been a long-standing and important issue in physics, but direct evidence of its existence is lacking. This work aims to elucidate the mystery and show that the dark matter hypothesis is unnecessary. We can nicely reproduce the observed rotation curves using only conventional Newtonian dynamics based on experimental surface brightness profiles of several galaxies. Our success is based on realizing that the mass radial distribution follows a stretched exponentia...

We present a method to investigate relativistic effects arising from large masses. The method is non-perturbative and employs a mean-field approximation and gravitational lensing. Using this method and a basic model of disk galaxy, we find that relativistic corrections to the rotation curves of disk galaxies are significant at large galactic radii. The model predicts a strong correlation between the inferred galactic dark mass and the galactic disk thickness, which we verifie...

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 considered convincing, thanks in part to observations of the rotation curves of galaxies. This dark matter should be present at multiple scales, in the solar neighborhood, our Galaxy, near and distant galaxies, clusters of galaxies, and the en...

One key piece of evidence for dark matter is the flat rotation curve problem: the disagreement between measured galactic rotation curves and their luminous mass. A novel solution to this problem is presented here. A model of relativistic frame effects on Doppler shifts due to the slightly curved frames of an emitting galaxy and the Milky Way is derived. This model predicts observed Doppler shifted spectra (in excess of the luminous mass) based only on the observed luminous ma...

Dark matter is the generally accepted paradigm in astrophysics and cosmology as a solution to the higher rate of rotation in galaxies, among many other reasons. But since there are still some problems encountered by the standard dark matter paradigm at the galactic scale, we have resorted to an alternative solution, similar to Milgrom's Modified Newtonian dynamics (MOND). Here, we have assumed that: (i) either the gravitational constant, G, is a function of distance (scale): ...

We analyze the recently obtained static and spherically symmetric solution of the Spinor Theory of Gravity (STG) which, in the weak field limit, presents an effective Newtonian potential that contains an extra logarithmic behavior. We apply this solution to the description of the galaxy rotation curves finding an interesting analogy with the dark matter halo profile proposed by Navarro, Frenk and White.

There are two observations of galaxies that can offer some insight into the nature of the dark matter (DM), namely the rotation curves and the gravitational lensing. While the first one can be studied using the Newtonian limit, the second one is completely relativistic. Each one separately can not determine the nature of DM, but both together give us key information about this open problem. In this work we use a static and spherically symmetric metric to model the DM halo in ...

It has recently been suggested that observed galaxy rotation curves can be accounted for by general relativity without recourse to dark-matter halos. A number of objections have been raised, which have been addressed by the authors. Here, the calculation of tangential velocity is questioned.

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 universe, then, having a cosmological character. A formal limiting radius for galaxies depending on cosmological parameters is given. The empirical conclusions derived from the theory of M. Milgrom and J. Bekenstein arise as direct consequences o...

Typically, stars in galaxies have higher velocities than predicted by Newtonian gravity in conjunction with observable galactic matter. To account for the phenomenon, some researchers modified Newtonian gravitation; others introduced dark matter in the context of Newtonian gravity. We employed general relativity successfully to describe the galactic velocity profiles of four galaxies: NGC 2403, NGC 2903, NGC 5055 and the Milky Way. Here we map the density contours of the gala...