scholarly journals Conformal gravity does not predict flat galaxy rotation curves

2021 ◽  
Vol 104 (6) ◽  
Author(s):  
M. P. Hobson ◽  
A. N. Lasenby
Keyword(s):  
Conformal Gravity ◽  
Rotation Curves ◽  
Galaxy Rotation Curves

scholarly journals Fitting dwarf galaxy rotation curves with conformal gravity

2012 ◽  
Vol 421 (2) ◽  
pp. 1273-1282 ◽  
Author(s):  
James G. O’Brien ◽  
Philip D. Mannheim
Keyword(s):  
Dwarf Galaxy ◽  
Conformal Gravity ◽  
Rotation Curves ◽  
Galaxy Rotation Curves

scholarly journals Galaxy Rotation Curves in Covariant Hořava-Lifshitz Gravity

Galaxies ◽  
2013 ◽  
Vol 2 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Jean Alexandre ◽  
Martyna Kostacinska
Keyword(s):  
Rotation Curves ◽  
Galaxy Rotation Curves

scholarly journals MODIFIED GRAVITY AS A COMMON CAUSE FOR COSMIC ACCELERATION AND FLAT GALAXY ROTATION CURVES

2012 ◽  
Vol 21 (11) ◽  
pp. 1242002 ◽  
Author(s):  
PRITI MISHRA ◽  
TEJINDER P. SINGH
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Cosmic Acceleration ◽  
Accelerating Universe ◽  
Rotation Curves ◽  
Common Cause ◽  
Order Of Magnitude ◽  
Flat Rotation Curves ◽  
Acceleration Of The Universe ◽  
Galaxy Rotation Curves

Flat galaxy rotation curves and the accelerating Universe both imply the existence of a critical acceleration, which is of the same order of magnitude in both the cases, in spite of the galactic and cosmic length scales being vastly different. Yet, it is customary to explain galactic acceleration by invoking gravitationally bound dark matter, and cosmic acceleration by invoking a "repulsive" dark energy. Instead, might it not be the case that the flatness of rotation curves and the acceleration of the Universe have a common cause? In this essay we propose a modified theory of gravity. By applying the theory on galactic scales we demonstrate flat rotation curves without dark matter, and by applying it on cosmological scales we demonstrate cosmic acceleration without dark energy.

scholarly journals Elongated Gravity Sources as an Analytical Limit for Flat Galaxy Rotation Curves

Universe ◽  
2021 ◽  
Vol 7 (9) ◽  
pp. 346
Author(s):  
Felipe J. Llanes-Estrada
Keyword(s):  
Galactic Plane ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Small Scale ◽  
Scaling Exponent ◽  
Rotation Curves ◽  
Central Mass ◽  
Filamentary Structure ◽  
Analytical Limit ◽  
Galaxy Rotation Curves

The flattening of spiral-galaxy rotation curves is unnatural in view of the expectations from Kepler’s third law and a central mass. It is interesting, however, that the radius-independence velocity is what one expects in one less dimension. In our three-dimensional space, the rotation curve is natural if, outside the galaxy’s center, the gravitational potential corresponds to that of a very prolate ellipsoid, filament, string, or otherwise cylindrical structure perpendicular to the galactic plane. While there is observational evidence (and numerical simulations) for filamentary structure at large scales, this has not been discussed at scales commensurable with galactic sizes. If, nevertheless, the hypothesis is tentatively adopted, the scaling exponent of the baryonic Tully–Fisher relation due to accretion of visible matter by the halo comes out to reasonably be 4. At a minimum, this analytical limit would suggest that simulations yielding prolate haloes would provide a better overall fit to small-scale galaxy data.

scholarly journals Excluded Volume for Flat Galaxy Rotation Curves in Newtonian Gravity and General Relativity

Symmetry ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 398 ◽  
Author(s):  
Rand Dannenberg
Keyword(s):  
General Relativity ◽  
Gravitational Constant ◽  
Excluded Volume ◽  
Newtonian Gravity ◽  
Least Action Principle ◽  
Rotation Curves ◽  
Least Action ◽  
A Charge ◽  
Vacuum Solutions ◽  
Galaxy Rotation Curves

Using the classical vacuum solutions of Newtonian gravity that do not explicitly involve matter, dark matter, or the gravitational constant, subject to an averaging process, a form of gravity relevant to the flattening of galaxy rotation curves results. The latter resembles the solution found if the vacuum is simply assigned a gravitational field density, and a volume of the vacuum is then excluded, with no averaging process. A rationale then follows for why these terms would become important on the galactic scale. Then, a modification of General Relativity, motivated by the Newtonian solutions, that are equivalent to a charge void, is partially defined and discussed in terms of a least action principle.

scholarly journals On galaxy rotation curves from a continuum mechanics approach to modified gravity

2018 ◽  
Vol 27 (02) ◽  
pp. 1850007 ◽  
Author(s):  
Christian G. Böhmer ◽  
Nicola Tamanini ◽  
Matthew Wright
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
Continuum Mechanics ◽  
Modified Gravity ◽  
Galactic Rotation ◽  
Dark Matter Halos ◽  
Additional Structure ◽  
Rotation Curves ◽  
Small Deviations ◽  
Galaxy Rotation Curves

We consider a modification of General Relativity motivated by the treatment of anisotropies in Continuum Mechanics. The Newtonian limit of the theory is formulated and applied to galactic rotation curves. By assuming that the additional structure of spacetime behaves like a Newtonian gravitational potential for small deviations from isotropy, we are able to recover the Navarro–Frenk–White profile of dark matter halos by a suitable identification of constants. We consider the Burkert profile in the context of our model and also discuss rotation curves more generally.

scholarly journals Testing feedback-modified dark matter haloes with galaxy rotation curves: estimation of halo parameters and consistency with ΛCDM scaling relations

2016 ◽  
Vol 466 (2) ◽  
pp. 1648-1668 ◽  
Author(s):  
Harley Katz ◽  
Federico Lelli ◽  
Stacy S. McGaugh ◽  
Arianna Di Cintio ◽  
Chris B. Brook ◽  
...  
Keyword(s):  
Dark Matter ◽  
Scaling Relations ◽  
Rotation Curves ◽  
Galaxy Rotation Curves

scholarly journals Spiral galaxy rotation curves in the Horava-Lifshitz gravity theory

2012 ◽  
Vol 423 (1) ◽  
pp. 141-148 ◽  
Author(s):  
V. F. Cardone ◽  
M. Capone ◽  
N. Radicella ◽  
M. L. Ruggiero
Keyword(s):  
Spiral Galaxy ◽  
Gravity Theory ◽  
Rotation Curves ◽  
Galaxy Rotation Curves
Sign in / Sign up

Export Citation Format

Share Document