Related papers: Errors in equations for galaxy rotation speeds
The dark matter accretion theory (around a central body) of the author on the basis of his 5-dimensional Projective Unified Field Theory (PUFT) is applied to the orbital motion of stars around the center of the Galaxy. The departure of the…
The role of gravity is crucial in astrophysics. It determines the evolution of any system, over an enormous range of time and space scales. Astronomical stellar systems as composed by N interacting bodies represent examples of…
Advances in instrumentation have recently extended detailed measurements of gas kinematics to large samples of high-redshift galaxies. Relative to most nearby, thin disk galaxies, in which gas rotation accurately traces the gravitational…
Mapping the dark matter distribution across our Galaxy represents a central challenge for the near future as a new generation of space-borne and ground-based astronomical surveys swiftly comes online. Here we present a synopsis of the…
This paper investigates the potential of Machian Gravity (MG), a five-dimensional theory of gravity, to explain the acceleration law governing rotationally bound systems, in particular spiral galaxies. MG was proposed as a framework capable…
We present the results from the analysis of galaxy rotation curves with Verlinde's emergent gravity. We use the data in the SPARC (Spitzer Photometry and Accurate Rotation Curves) database, which contains a sample of 175 nearby disk…
CONTENTS: 1. INTRODUCTION 2. GRAVITATIONAL INSTABILITY 3. MEASURING PECULIAR VELOCITIES 4. ANALYSIS OF OBSERVED PECULIAR VELOCITIES 5. PREDICTED MOTIONS FROM THE GALAXY DISTRIBUTION 6. TESTING BASIC HYPOTHESES 7. THE INITIAL FLUCTUATIONS 8.…
Dwarf galaxies are ideal laboratories to test dark matter models and alternative theories because their dynamical mass (from observed kinematics) largely outweighs their baryonic mass (from gas and stars). In most star-forming dwarfs, cold…
This paper discusses the observed at rotation curves of galaxies in the context of noncommutative geometry. The energy density of such a geometry is diffused throughout a region due to the uncertainty encoded in the coordinate commutator.…
Recent work on the equilibrium and stability of ellipsoidal stellar systems is reviewed. The absence of constant-density cores in early-type galaxies implies that chaos and high-order resonances are generic features of the motion in…
The mass distribution of galaxy clusters can be determined from the study of the projected phase-space distribution of cluster galaxies. The main advantage of this method as compared to others, is that it allows determination of cluster…
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…
In previous works, entropic gravity and ungravity have been considered as possible solutions to the dark energy and dark matter problems. To test the viability of these models, modifications to planetary orbits are calculated for ungravity…
Understanding of the nature of dark energy, which appears to drive the expansion of the universe, is one of the central problems of physical cosmology today. In an earlier paper [Daly & Djorgovski (2003)] we proposed a novel method to…
For relativistic stars rotating slowly and differentially with a positive angular velocity, some properties in relation to the positiveness of the rate of rotational dragging and of the angular momentum density are derived. Also, a new…
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…
An accurate knowledge of the dark matter distribution in the Milky Way is of crucial importance for galaxy formation studies and current searches for particle dark matter. In this paper we set new dynamical constraints on the Galactic dark…
One of the goals of current cosmological studies is the determination of the expansion and acceleration rates of the universe as functions of redshift, and the determination of the properties of the dark energy that can explain these…
We consider the gravitational potential and the gravitational rotation field generated by an spherical mass distribution with exponential density, when the force between any two mass elements is not the usual Newtonian one, but some general…
The increasing number and variety of extrasolar planets illustrates the importance of characterizing planetary perturbations. Planetary orbits are typically described by physically intuitive orbital elements. Here, we explicitly express the…