Related papers: Polar ring galaxies as tests of gravity
Radio-loud neutron stars known as pulsars allow a wide range of experimental tests for fundamental physics, ranging from the study of super-dense matter to tests of general relativity and its alternatives. As a result, pulsars provide…
Neutron stars are versatile in their application to studying various important aspects of fundamental physics, in particular strong-field gravity tests and the equation of state for super-dense nuclear matter at low temperatures. However,…
MONDian dark matter (MDM) is a new form of dark matter quantum that naturally accounts for Milgrom's scaling, usually associated with modified Newtonian dynamics (MOND), and theoretically behaves like cold dark matter (CDM) at cluster and…
We investigate galactic rotation curves in $f(T)$ gravity, where $T$ represents a torsional quantity. Our study centers on the particular Lagrangian $f(T)=T+\alpha{T^n}$, where $|n|\neq 1$ and $\alpha$ is a small unknown constant. To do…
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…
The dynamical stability of disk galaxies is sensitive to whether their anomalous rotation curves are caused by dark matter halos or Milgromian Dynamics (MOND). We investigate this by setting up a MOND model of M33. We first simulate it in…
The dynamics of an elliptical galaxy within a couple of effective radii can be probed effectively by stars. However, at larger distances planetary nebulae (PNe) replace stars as the tracer of the dynamics. Making use of the motion of PNe,…
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 hydrodynamic cosmological simulation, TNG50, is employed to conduct an analysis of multi-spin galaxies that exhibit ringed structures composed of gas and stars that orbit nearly perpendicular around a host galaxy, known as polar ring…
Pulsars are wonderful gravitational probes. Their tiny size and stellar mass give their rotation periods a stablility comparable to that of atomic frequency standards. This is especially true of the rapidly rotating "millisecond pulsars"…
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…
Rotation curves of dark-matter-dominated galaxies measure the mass profiles of galactic halos and thereby test theories of their cosmological origin. While attention has focused lately on the possible discrepancy at small galactocentric…
We review some recent work by Mannheim and O'Brien on the systematics of galactic rotation curves in the conformal gravity theory. In this work the conformal theory was applied to a comprehensive, high quality sample of spiral galaxies…
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…
Galaxy rotation curves determined observationally out to a radius well beyond the galaxy cores can provide a critical test of modified gravity models without dark matter. The predicted rotational velocity curve obtained from…
The gravitational field of Spiral galaxies is well traced by their rotation curves. Only recently it has become of extreme interest that the latter form a family ruled by two parameters of the {\it luminous} component: the disk length-scale…
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.
It has long been known that Newtonian dynamics applied to the visible matter in galaxies and clusters does not correctly describe the dynamics of those systems. While this is generally taken as evidence for dark matter it is in principle…
General Relativity is a hugely successful description of gravitation. However, both theory and observations suggest that General Relativity might have significant classical and quantum corrections in the Strong Gravity regime. Testing the…
The observed flat rotation curves of galaxies require either the presence of dark matter in Newtonian gravitational potentials or a significant modification to the theory of gravity at galactic scales. Detecting relativistic Doppler shifts…