scholarly journals Galaxy Rotation Curves without Nonbaryonic Dark Matter

2006 ◽  
Vol 636 (2) ◽  
pp. 721-741 ◽  
Author(s):  
J. R. Brownstein ◽  
J. W. Moffat
Keyword(s):  
Dark Matter ◽  
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 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 Galaxy rotation curves using a non-parametric regression method: core, cuspy and fuzzy scalar field dark matter models

2019 ◽  
Vol 488 (4) ◽  
pp. 5127-5144 ◽  
Author(s):  
Lizbeth M Fernández-Hernández ◽  
Ariadna Montiel ◽  
Mario A Rodríguez-Meza
Keyword(s):  
Dark Matter ◽  
Selection Criteria ◽  
Spiral Galaxies ◽  
Information Criterion ◽  
Volume Density ◽  
Rotation Curves ◽  
Fuzzy Models ◽  
Galaxy Rotation Curves ◽  
Statistical Criteria ◽  
Non Parametric

ABSTRACT We present a non-parametric reconstruction of the rotation curves (RCs) for 88 spiral galaxies using the LOESS (locally weighted scatterplot smoothing) + SIMEX (simulation and extrapolation) technique. In order to compare methods, we also use a parametric approach, assuming core and cuspy dark matter (DM) profiles: pseudo-isothermal (PISO), Navarro−Frenk–White (NFW), Burkert, Spano, the soliton, and two fuzzy soliton + NFW. As a result of these two approaches, a comparison of the RCs obtained is carried out by computing the distance between the central curves and the distance between the 1σ error bands. Furthermore, we perform a model selection according to two statistical criteria, the Bayesian information criterion and the value of $\chi ^2_{\rm red}$. We work with two groups. The first is a comparison between PISO, NFW, Spano and Burkert, showing that Spano is the most favoured model satisfying our selection criteria. For the second group, we select the soliton, NFW and fuzzy models, resulting in soliton as the best model. Moreover, according to the statistical tools and non-parametric reconstruction, we are able to classify galaxies as core or cuspy. Finally, using a Markov chain Monte Carlo method, for each of the DM models we compute the characteristic surface density, μDM = ρsrs, and the mass within 300 pc. We find that there is a common mass for spiral galaxies of the order of 107 M⊙, which is in agreement with results for dSph Milky Way satellites, independent of the model. This result is also consistent with our finding that there is a constant characteristic volume density of haloes. Finally, we also find that μDM is not constant, which is in tension with the literature.

scholarly journals Galaxy Rotation Curves in the µ-Deformation Based Approach to Dark Matter

2019 ◽  
Vol 64 (11) ◽  
pp. 1042 ◽  
Author(s):  
A. M. Gavrilik ◽  
I. I. Kachurik ◽  
M. V. Khelashvili
Keyword(s):  
Dark Matter ◽  
Physical Meaning ◽  
Deformation Parameter ◽  
Einstein Condensate ◽  
Rotation Curves ◽  
Density Profiles ◽  
Emden Equation ◽  
Bose Einstein Condensate ◽  
Bose Einstein ◽  
Galaxy Rotation Curves

We elaborate further the м-deformation-based approach to the modeling of dark matter, in addition to the earlier proposed use of м-deformed thermodynamics. Herein, we construct м-deformed analogs of the Lane–Emden equation (for density profiles) and find their solutions. Using these, we plot the rotation curves for a number of galaxies. Different curves describing the chosen galaxies are labeled by respective (different) values of the deformation parameter м. As a result, the use of м-deformation leads to the improved agreement with observational data. For all the considered galaxies, the obtained rotation curves (labeled by м) agree better with data, as compared to the well-known Bose–Einstein condensate model results of T. Harko. Besides, for five of the eight cases of galaxies, we find a better picture for rotation curves, than the corresponding Navarro–Frenk–White (NFW) curves. The possible physical meaning of the parameter м basic for this version of м-deformation is briefly discussed.

scholarly journals Pairs of Galaxies in Low Density Regions of a Combined Redshift Catalog

1990 ◽  
Vol 124 ◽  
pp. 19-23
Author(s):  
Jane C. Charlton ◽  
Edwin E. Salpeter
Keyword(s):  
Dark Matter ◽  
Radial Velocity ◽  
Low Density ◽  
Rotation Curves ◽  
Large Groups ◽  
Galaxy Rotation Curves

AbstractThe distributions of projected separations and radial velocity differences of pairs of galaxies in the CfA and SSRS redshift catalogs are examined. We focus on pairs that fall in low density environments rather than in clusters or large groups. The projected separation distribution is nearly flat, while uncorrelated galaxies would have given one linearly rising with rp. There is no break in this curve even below 50 kpc, the minimum halo size consistent with measured galaxy rotation curves. The significant number of pairs at small separations is inconsistent with the N-body result that galaxies with overlapping halos will rapidly merge, unless there are significant amounts of matter distributed out to a few hundred kpc of the galaxies. This dark matter may either be in distinct halos or more loosely distributed. Large halos would allow pairs at initially large separations to head toward merger, replenishing the distribution at small separations. In the context of this model, we estimate that roughly 10 — 25% of these low density galaxies are the product of a merger, compared with the elliptical / S0 fraction of 18%, observed in low density regions of the sample.

scholarly journals Dark-matter halo shapes from fits to SPARC galaxy rotation curves

2021 ◽  
Author(s):  
Felipe J. Llanes-Estrada ◽  
Adriana Bariego Quintana ◽  
Oliver Manzanilla Carretero
Keyword(s):  
Dark Matter ◽  
Dark Matter Halo ◽  
Rotation Curves ◽  
Galaxy Rotation Curves

scholarly journals The Phantom Dark Matter Halos of the Local Volume in the Context of Modified Newtonian Dynamics

2021 ◽  
Vol 923 (1) ◽  
pp. 68
Author(s):  
P.-A. Oria ◽  
B. Famaey ◽  
G. F. Thomas ◽  
R. Ibata ◽  
J. Freundlich ◽  
...  
Keyword(s):  
Dark Matter ◽  
External Field ◽  
Cold Dark Matter ◽  
Average Density ◽  
Mass Relation ◽  
Rotation Curves ◽  
Local Volume ◽  
Linear Version ◽  
Observational Estimate ◽  
Galaxy Rotation Curves

Abstract We explore the predictions of Milgromian gravity (MOND) in the local universe by considering the distribution of the “phantom” dark matter (PDM) that would source the MOND gravitational field in Newtonian gravity, allowing an easy comparison with the dark matter framework. For this, we specifically deal with the quasi-linear version of MOND (QUMOND). We compute the “stellar-to-(phantom)halo mass relation” (SHMR), a monotonically increasing power law resembling the SHMR observationally deduced from spiral galaxy rotation curves in the Newtonian context. We show that the gas-to-(phantom)halo mass relation is flat. We generate a map of the Local Volume in QUMOND, highlighting the important influence of distant galaxy clusters, in particular Virgo. This allows us to explore the scatter of the SHMR and the average density of PDM around galaxies in the Local Volume, ΩPDM ≈ 0.1, below the average cold dark matter density in a ΛCDM universe. We provide a model of the Milky Way in its external field in the MOND context, which we compare to an observational estimate of the escape velocity curve. Finally, we highlight the peculiar features related to the external field effect in the form of negative PDM density zones in the outskirts of each galaxy, and test a new analytic formula for computing galaxy rotation curves in the presence of an external field in QUMOND. While we show that the negative PDM density zones would be difficult to detect dynamically, we quantify the weak-lensing signal they could produce for lenses at z ∼ 0.3.

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