The Carmeli Metric Correctly Describes Spiral Galaxy Rotation Curves

The metric by Carmeli accurately produces the Tully-Fisher type relation in spiral galaxies, a relation showing the fourth power of the rotation speed proportional to the mass of the galaxy. And therefore it is claimed that it is also no longer necessary to invoke dark matter to explain the anomalous dynamics in the arms of spiral galaxies. An analysis is presented here showing Carmeli’s 5 dimensional space-time-velocity metric can also indeed describe the rotation curves of spiral galaxies based on the properties of the metric alone.     

The Persistent Problem of Spiral Galaxies

The current explanation for spiral galaxies is that density waves in a spiral form rotate through the disks of these galaxies, continually forming new arms of hot bright stars and excited gas. The discussion here shows that many observed properties of spiral galaxies contradict this assumed density wave mechanism. Alternatively, it has been clear since the early 1950's that galaxies characteristically eject material from their nuclei. A number of astronomers have presented evidence that it is those ejections from the central regions of rotating galaxies that are responsible for the spiral arms. The evidence is reviewed and evaluated here, and it is concluded that the form and nature of the arms, their magnetic fields and rotational velocity characteristics, can best be explained by ejections of material, including plasma, from which the spiral arm stars are formed. This conclusion furnishes an answer to the long-standing problem of how the magnetic fields arise in the outer regions of spirals. Perhaps most importantly, the formation and renewal of spiral arms by ejection of plasma does not require them to be in rotation only under the pull of gravitational forces. If rotational energy is transferred to outer regions by ejections, the current interpretation of rotation curves may overestimate masses of spiral galaxies. If the problem of "missing mass" is diminished, so is the necessity for exotic suggestions to account for this undetected matter.     

The effect of a gravitational induction force on the stellar orbits in galaxies

This paper explores the effect of a gravitational induction force, similar to gravito-electromagnetism but of several orders of magnitude larger, on a spiral galaxy. This would provide, because of the huge amount of mass currents associated with spirals, a rather large gravitational induction force. Standard gravitational dynamics is modified by adding an anti-symmetric force tensor analogous to electromagnetism. By choosing a special free space solution to the Einstein field equations, it was found that the resulting force field would drop off by an r ⁻¹ rather than an r ⁻² rule. Thus this new induction force would grow to dominance over the large distances associated with galaxies. Any r ⁻¹ force will produce the flat rotation curves that are observed in disk galaxies as well as explain the Tully-Fisher relationship. It would also explain why the inner core of the spirals remain Newtonian. Quite surprisingly, this simple hypothesis also seems to offer explanations for many other observed phenomena as well.     

Lopsided spiral galaxies

The light distribution in the disks of many galaxies is ‘lopsided’ with a spatial extent much larger along one half of a galaxy than the other, as seen in M101. Recent observations show that the stellar disk in a typical spiral galaxy is significantly lopsided, indicating asymmetry in the disk mass distribution. The mean amplitude of lopsidedness is 0.1, measured as the Fourier amplitude of the m=1$m=1$ component normalized to the average value. Thus, lopsidedness is common, and hence it is important to understand its origin and dynamics. This is a new and exciting area in galactic structure and dynamics, in contrast to the topic of bars and two-armed spirals (m=2)$(m=2)$ which has been extensively studied in the literature. Lopsidedness is ubiquitous and occurs in a variety of settings and tracers. It is seen in both stars and gas, in the outer disk and the central region, in the field and the group galaxies. The lopsided amplitude is higher by a factor of two for galaxies in a group.     

Magnetic fields in spiral galaxies

Radio polarization observations have revealed large-scale magnetic fields in spiral galaxies. The average total field strength most probably increases with the rate of star formation. The uniform field generally follows the orientation of the optical spiral arms, but is often strongest outside the arms. Long magnetic-field filaments are seen, sometimes up to a 30 kpc length. The field seems to be anchored in large gas clouds and is inflated out of the disk, e.g. by a galactic wind. The field in radio halos around galaxies is highly uniform in limited regions, resembling the structure of the solar corona. The detection of Faraday rotation in spiral galaxies excludes the existence of large amounts of antimatter. The distribution of Faraday rotation in the disks shows two different large-scale structures of the interstellar field; axisymmetric-spiral and bisymmetric-spiral, which are interpreted as two modes of the galactic dynamo driven by differential rotation     

Gravity with Extra Dimensions and Dark Matter Interpretation: Phenomenological Example via Miyamoto–Nagai Galaxy

Any connection between dark matter and extra dimensions is revealed by the effective energy-momentum tensor associated with the theory. In order to investigate and test such a relationship, we examine a higher-dimensional space–time endowed with a factorizable general metric with a configuration such that its density profile coincides with the Newtonian potential for disk galaxies. An appropriate solution representing stratifications of mass in the central-bulge and disk part of galaxies, e.g., the Miyamoto–Nagai ansatz, is used to solve the Einstein equations. We compute the stable rotation curves of such systems and, with no adjustable parameters, accurately recover the observational data for flat or not asymptotically flat galaxy rotation curves. We present examples of density profiles and compare them to the profile obtained from purely Newtonian potentials.     

Spiral galaxies rotation curves with a logarithmic corrected newtonian gravitational potential

We analyze the rotation curves of 10 spiral galaxies with a newtonian potential corrected with an extra logarithmic term. The logarithmic correction can have its origin from fundamental frameworks, like string theories or effective models of gravity due to quantum effects. There is also a connection with some toy models resulting from TeVeS. We represent the spiral galaxies as a thin disk. There is a new constant associated with the extra term in the potential. The rotation curve of the chosen sample of spiral galaxies is well reproduced for a narrow range of the new constant. The compatibility of this correction with local physics is discussed.     

Landau excitation of spiral density waves in an inhomogeneous disk of stars

Drift-resonant Landau excitation of spiral density waves in a stellar disk of flat galaxies is proposed. This excitation of waves is suggested as a mechanism for the formation of structural features such as spiral arms and the slow dynamical relaxation of galaxies in a regime of hydrodynamical Jeans-type stability.     

Comparing dark matter models,modified Newtonian dynamics and modified gravity in accounting for galaxy rotation curves

We compare six models(including the baryonic model,two dark matter models,two modified Newtonian dynamics models and one modified gravity model) in accounting for galaxy rotation curves.For the dark matter models,we assume NFW profile and core-modified profile for the dark halo,respectively.For the modified Newtonian dynamics models,we discuss Milgrom's MOND theory with two different interpolation functions,the standard and the simple interpolation functions.For the modified gravity,we focus on Moffat's MSTG theory.We fit these models to the observed rotation curves of 9 high-surface brightness and 9 low-surface brightness galaxies.We apply the Bayesian Information Criterion and the Akaike Information Criterion to test the goodness-of-fit of each model.It is found that none of the six models can fit all the galaxy rotation curves well.Two galaxies can be best fitted by the baryonic model without involving nonluminous dark matter.MOND can fit the largest number of galaxies,and only one galaxy can be best fitted by the MSTG model.Core-modified model fits about half the LSB galaxies well,but no HSB galaxies,while the NFW model fits only a small fraction of HSB galaxies but no LSB galaxies.This may imply that the oversimplified NFW and core-modified profiles cannot model the postulated dark matter haloes well.     

Inhomogeneous exact solution in brane gravity and its applications

Considering an inhomogeneous brane embedded in a five dimensional constant curvature bulk, we find the non-static and spherically symmetric exact solutions of the Einstein equations on the brane. With different choices of the parameters, one interesting case/solution is studied. We show that an inhomogeneous brane model can explain the accelerated expansion of the universe at large distance scales and also the galaxy rotation curves of spiral galaxies without assuming the existence of dark matter or new modified theories at the galactic scales.     

A linear theory of resonance structures in spiral galaxies

The resonance mechanism for the formation of galactic spirals is considered. Expressions are derived for the resonance responses of disks with circular and nearly circular stellar orbits. The spiral responses produced by the central oval-shaped structures (bars) available in many galaxies are shown to have the characteristic properties of the spirals observed in these galaxies. In the most interesting case of a quasi-steady state, the spiral responses possess a similarity property: the spiral thickness and inclination are proportional to the mean size of an epicycle (an analog of the Larmor circle in plasma).     

Geometric diagnostics of complex patterns: spiral defect chaos

Motivated by the observation of spiral patterns in a wide range of physical, chemical, and biological systems, we present an automated approach that aims at characterizing quantitatively spiral-like elements in complex stripe-like patterns. The approach provides the location of the spiral tip and the size of the spiral arms in terms of their arc length and their winding number. In addition, it yields the number of pattern components (Betti number of order 1), as well as their size and certain aspects of their shape. We apply the method to spiral defect chaos in thermally driven Rayleigh-Benard convection and find that the arc length of spirals decreases monotonically with decreasing Prandtl number of the fluid and increasing heating. By contrast, the winding number of the spirals is nonmonotonic in the heating. The distribution function for the number of spirals is significantly narrower than a Poisson distribution. The distribution function for the winding number shows approximately an exponential decay. It depends only weakly on the heating, but strongly on the Prandtl number. Large spirals arise only for larger Prandtl numbers (Pr approximately > 1). In this regime the joint distribution for the spiral length and the winding number exhibits a three-peak structure, indicating the dominance of Archimedean spirals of opposite sign and relatively straight sections. For small Prandtl numbers the distribution function reveals a large number of small compact pattern components.     

Evolution of the Plasma Universe: II. The Formation of Systems of Galaxies

The model of the plasma universe, inspired by totally unexpected phenomena observed with the advent and application of fully three-dimensional electromagnetic particle-in-cell simulations to filamentary plasmas, consists of studying the interaction between field-aligned current-conducting, galactic-dimensioned plasma sheets or filaments (Birkeland currents). In a preceding paper, the evolution of the interaction spanned some 108-109 years, where simulational analogs of synchrotron-emitting double radio galaxies and quasars were discovered. This paper reports the evolution through the next 109-5 × 109 years. In particular, reconfiguration and compression of tenuous cosmic plasma due to the self-consistent magnetic fields from currents conducted through the filaments leads to the formation of elliptical, peculiar, and barred and normal spiral galaxies. The importance of the electromagnetic pinch in producing condense states and initiating gravitational collapse of dusty galactic plasma to stellisimals, then stars, is discussed. Simulation data are directly compared to galaxy morphology types, synchrotron flux, Hi distributions, and fine detail structure in rotational velocity curves. These comparisons suggest that knowledge obtained from laboratory, simulation, and magnetospheric plasmas offers not only to enhance our understanding of the universe, but also to provide feedback information to laboratory plasma experiments from the unprecedented source of plasma data provided by the plasma universe.     

The Hubble law and the spiral structures of galaxies from equations of motion in general relativity

Fully exploiting the Lie group that characterizes the underlying symmetry of general relativity theory, Einstein's tensor formalism factorizes, yielding a generalized (16-component) quaternion field formalism. The associated generalized geodesic equation, taken as the equation of motion of a star, predicts the Hubble law from one approximation for the generally covariant equations of motion, and the spiral structure of galaxies from another approximation. These results depend on the imposition of appropriate boundary conditions. The Hubble law follows when the boundary conditions derive from the oscillating model cosmology, and not from the other cosmological models. The spiral structures of the galaxies follow from the same boundary conditions, but with a different time scale than for the whole universe. The solutions that imply the spiral motion areFresnel integrals. These predict the star's motion to be along the “Cornu Spiral.” The part of this spiral in the first quadrant is the imploding phase of the galaxy, corresponding to a motion with continually decreasing radii, approaching the galactic center as time increases. The part of the “Cornu Spiral” in the third quadrant is the exploding phase, corresponding to continually increasing radii, as the star moves out from the hub. The spatial origin in the coordinate system of this curve is the inflection point, where the explosion changes to implosion. The two- (or many-) armed spiral galaxies are explained here in terms of two (or many) distinct explosions occurring at displaced times, in the domain of the rotating, planar galaxy.     

Multi-armed spirals and multi-pairs antispirals in spatial rock–paper–scissors games

We study the formation of multi-armed spirals and multi-pairs antispirals in spatial rock–paper–scissors games with mobile individuals. We discover a set of seed distributions of species, which is able to produce multi-armed spirals and multi-pairs antispirals with a finite number of arms and pairs based on stochastic processes. The joint spiral waves are also predicted by a theoretical model based on partial differential equations associated with specific initial conditions. The spatial entropy of patterns is introduced to differentiate the multi-armed spirals and multi-pairs antispirals. For the given mobility, the spatial entropy of multi-armed spirals is higher than that of single armed spirals. The stability of the waves is explored with respect to individual mobility. Particularly, we find that both two armed spirals and one pair antispirals transform to the single armed spirals. Furthermore, multi-armed spirals and multi-pairs antispirals are relatively stable for intermediate mobility. The joint spirals with lower numbers of arms and pairs are relatively more stable than those with higher numbers of arms and pairs. In addition, comparing to large amount of previous work, we employ the no flux boundary conditions which enables quantitative studies of pattern formation and stability in the system of stochastic interactions in the absence of excitable media.     

Balance of dark and luminous mass in rotating galaxies

A fine balance between dark and baryonic mass is observed in spiral galaxies. As the contribution of the baryons to the total rotation velocity increases, the contribution of the dark matter decreases by a compensating amount. This poses a fine-tuning problem for galaxy formation models, and may point to new physics for dark matter particles or even a modification of gravity.     

Interpretation of Rotation Curves of Spiral Galaxies in Modified Teleparallel Gravity

There is a significant difference between the calculation based on the theory of general relativity and observation of rotation curves of spiral galaxies. To describe this discrepancy, two distinct theories have been proposed so far： existence of dark matter and modification of underlying gravitational theory. In the absence of dark matter, it is assumed that the theory of general relativity on galactic scales needs to be modified. This letter is devoted to explaining this difference in a modified teleparMIeI gravity. We show that modified teleparallel gravity favors flatness of rotation curves of spiral galaxies much in the same way as observation shows.     

Interpretation of Rotation Curves of Spiral Galaxies in Modified Teleparallel Gravity

There is a significant difference between the calculation based on the theory of general relativity and observation of rotation curves of spiral galaxies. To describe this discrepancy, two distinct theories have been proposed so far: existence of dark matter and modification of underlying gravitational theory. In the absence of dark matter, it is assumed that the theory of general relativity on galactic scales needs to be modified. This letter is devoted to explaining this difference in a modified teleparallel gravity. We show that modified teleparallel gravity favors flatness of rotation curves of spiral galaxies much in the same way as observation shows.     

Radio emission from interstellar neutral hydrogen

The emission line for neutral hydrogen at 1420 Mc/s is the only line so far discovered in radioastronomy. Since its mechanism of origin is completely understood, observations of this line provide direct information about conditions in interstellar space such as temperatures, densities and velocities. Extensive investigations of our own Milky Way system have shown clearly that it is a spiral galaxy similar to, but rather smaller than, the great spiral nebula in Andromeda. Our knowledge of the spiral structure of galaxies is far from complete; hydrogen-line measures of high-speed expansions in the centre of the Milky Way system may provide a clue to the understanding of this problem. In addition, determinations of the hydrogen content of different types of galaxy reinforce current theories which suggest that irregular galaxies evolve through the spiral form to elliptical galaxies.     

Mirror matter, mirror gravity and galactic rotational curves

We discuss astrophysical implications of the modified gravity model in which the two matter components, ordinary and dark, couple to separate gravitational fields that mix to each other through small mass terms. There are two spin-2 eigenstates: the massless graviton, which induces universal Newtonian attraction, and the massive one, which gives rise to the Yukawa-like potential which is repulsive between the ordinary and dark bodies. As a result for distances much smaller than the Yukawa radius r _m the gravitation strength between the two types of matter becomes vanishing. If r _m ～10 kpc, the typical size of a galaxy, there are interesting implications for the nature of dark matter. In particular, one can avoid the problem of the cusp that is typical for the cold dark matter halos. Interestingly, the flat shape of the rotational curves can be explained even in the case of the collisional and dissipative dark matter (as e.g. mirror matter), which cannot give the extended halos but instead must form galactic discs similarly to the visible matter. The observed rotational curves for the large, medium-size and dwarf galaxies can be nicely reproduced. We also briefly discuss possible implications for the direct search of dark matter.