scholarly journals Vertical Motion and the Thickness of Hi Disks: Implications for Galactic Mass Models

1983 ◽  
Vol 100 ◽  
pp. 69-76
Author(s):  
P. C. van der Kruit ◽  
G. S. Shostak
Keyword(s):  
Dark Matter ◽  
Mass Distribution ◽  
Rotation Curve ◽  
Spiral Galaxies ◽  
Galactic Plane ◽  
Vertical Motion ◽  
Late Type ◽  
Rotation Curves ◽  
Central Bulge ◽  
Local Value

Most studies of the mass distribution in spiral galaxies have been based on the observed rotation curves. A serious ambiguity in this approach has always been that the rotation curve contains in itself no information on the mass distribution in the direction perpendicular to the galactic plane. The usual assumption has been that the mass in late type galaxies is distributed as the light, namely outside the central bulge in a highly flattened disk. In recent years it has been found that the rotation curves decline little or not at all, indicating large increases in the local value of M/L with increasing galactocentric radius (e.g. Bosma and van der Kruit, 1979). On the basis of dynamical arguments involving stability it has been suspected that the material giving rise to the large values of M/L - the “dark matter” - is distributed in the halos of these galaxies, so that the assumption of a flat mass distribution would have to be wrong.

scholarly journals Cores vs. Cusps: Dark Matter Density Profiles in Spirals

2004 ◽  
Vol 220 ◽  
pp. 311-312
Author(s):  
Gianfranco Gentile ◽  
Uli Klein ◽  
Paolo Salucci ◽  
Daniela Vergani
Keyword(s):  
Dark Matter ◽  
Rotation Curve ◽  
Spiral Galaxies ◽  
Matter Density ◽  
Matter Distribution ◽  
Rotation Curves ◽  
Density Profiles ◽  
The Core ◽  
Dark Matter Distribution ◽  
A New Technique

We use photometric, Hα and Hi data to investigate the distribution of dark matter in spiral galaxies. A new technique for deriving the Hi rotation curve is presented. the final combined Hα+Hi rotation curves are symmetric, well resolved and extend to large radii. We perform the rotation curve decomposition into the luminous and dark matter contributions. the observations are confronted with different models of the dark matter distribution, including core-dominated and cusp-dominated halos as well as less conventional possibilities. the best agreement with the observations is found for the core-dominated halos.

scholarly journals Dissipation and Formation of Galactic Halos

1988 ◽  
Vol 130 ◽  
pp. 421-425
Author(s):  
George R. Blumenthal
Keyword(s):  
Dark Matter ◽  
Mass Distribution ◽  
Spiral Galaxies ◽  
Galactic Halos ◽  
Rotation Curves ◽  
Striking Effect

When protogalaxies collapse, the cooling and infall of what will become the visible galactic component affects the mass distribution of dissipationless dark matter particles which constitute the halo. For spiral galaxies, the reaction of the dissipationless halo can have a striking effect on the resulting rotation curves [1–5].

scholarly journals Halo Parameters of Spiral Galaxies

1987 ◽  
Vol 117 ◽  
pp. 133-133
Author(s):  
E. Athanassoula ◽  
A. Bosma ◽  
S. Papaioannou
Keyword(s):  
Dark Matter ◽  
Mass Distribution ◽  
Rotation Curve ◽  
Spiral Galaxies ◽  
Curve Analysis ◽  
Hollow Core ◽  
Constant Mass ◽  
Kinematical Data

We have made a rotation curve analysis of a sample of spiral galaxies for which both photometric and kinematical data of reasonable quality are available in the literature. From the photometric radial luminosity profile, assuming constant mass-to-light ratios for bulge and disk separately, we calculate a rotation curve due to the luminous mass in a galaxy. Comparison with the observed rotation velocities allows us to derive a halo rotation curve, which can be used to derive characteristic halo parameters. The decomposition into luminous and dark matter is not unique, with as extremes a “minimum” disk (M/L = 0) and a “maximum” disk (M/L as high as possible while requiring a realistic halo mass distribution without a hollow core).

scholarly journals Dark Matter in Spiral Galaxies

1995 ◽  
Vol 164 ◽  
pp. 205-214 ◽  
Author(s):  
P.C. Van Der Kruit
Keyword(s):  
Dark Matter ◽  
Mass Distribution ◽  
Spiral Galaxies ◽  
Short Discussion ◽  
Rotation Curves ◽  
Disk Mass

In this review I will concentrate on three questions concerning the issue of dark matter in spiral galaxies. In the first place (and for the most part) I will discuss the analysis of rotation curves and the question whether the “maximum–disk hypothesis” is valid. Then I will discuss independent measurements of the disk mass distribution from the thickness of stellar and HI disks. Then follows a review of estimates of the flattening of the dark halos and a short discussion on the possible nature of the dark matter.

scholarly journals Mass models of three southern late-type dwarf spirals

1985 ◽  
Vol 106 ◽  
pp. 95-96
Author(s):  
C. Carignan
Keyword(s):  
Dark Matter ◽  
Spatial Distribution ◽  
Rotation Curve ◽  
Spiral Galaxies ◽  
Theoretical Studies ◽  
Late Type ◽  
Fundamental Parameters ◽  
Luminous Matter ◽  
Scale Length

Although rotation-curve studies of spiral galaxies have unambiguously established the presence of dark matter, and theoretical studies have shown that its location is likely to be in a separate spheroidal halo component (Binney, 1978; Tubbs and Sanders, 1979; Monet, Richstone and Schechter, 1981), very little is known about its spatial distribution and its nature. Recently, Faber and Lin (Faber and Lin, 1983; Lin and Faber, 1983) have shown that, if one can get a rough idea of fundamental parameters like the halo scale length and the halo-to-disk ratio, it is also possible to put strong constraints on the nature of non-luminous matter.

scholarly journals Newtonian and modified newtonian gravitational simulation of spiral galaxies

2019 ◽  
Vol 11 (21) ◽  
pp. 20-27
Author(s):  
Bushra A. Ahmed
Keyword(s):  
Dark Matter ◽  
Rotation Curve ◽  
Spiral Galaxies ◽  
Stellar Dynamics ◽  
Gravitational Attraction ◽  
Rotation Curves ◽  
Modified Newtonian Dynamics ◽  
Newtonian Dynamics ◽  
Rotational Curve ◽  
Good Agreement

One of the most powerful tools for any stellar dynamics is the N-body simulation. In an N-body simulation the motion of N particles is followed under their mutual gravitational attraction. In this paper the gravitational N-body simulation is described to investigate Newtonian and non- Newtonian (modified Newtonian dynamics) interaction between the stars of spiral galaxies. It is shown that standard Newtonian interaction requires dark matter to produce the flat rotational curves of the systems under consideration, while modified Newtonian dynamics (MOND) theorem provides a flat rotational curve and gives a good agreement with the observed rotation curve; MOND was tested as an alternative to the dark matter hypothesis. So that MOND hypothesis has generated better rotation curves than Newtonian theorem.

scholarly journals The inner mass distribution of late-type spiral galaxies fromSAURONstellar kinematic maps

2016 ◽  
Vol 464 (2) ◽  
pp. 1903-1922 ◽  
Author(s):  
Veselina Kalinova ◽  
Glenn van de Ven ◽  
Mariya Lyubenova ◽  
Jesús Falcón-Barroso ◽  
Dario Colombo ◽  
...  
Keyword(s):  
Mass Distribution ◽  
Spiral Galaxies ◽  
Late Type

scholarly journals The Massive Dark Corona Of Our Galaxy

1996 ◽  
Vol 173 ◽  
pp. 175-176
Author(s):  
K.C. Freeman
Keyword(s):  
Rotation Curve ◽  
Spiral Galaxies ◽  
Galactic Center ◽  
Galactic Disk ◽  
Galactic Rotation ◽  
Rotation Curves ◽  
Stellar Component ◽  
The Galaxy ◽  
Galactic Rotation Curve

From their rotation curves, most spiral galaxies appear to have massive dark coronas. The inferred masses of these dark coronas are typically 5 to 10 times the mass of the underlying stellar component. I will review the evidence that our Galaxy also has a dark corona. Our position in the galactic disk makes it difficult to measure the galactic rotation curve beyond about 20 kpc from the galactic center. However it does allow several other indicators of the total galactic mass out to very large distances. It seems clear that the Galaxy does indeed have a massive dark corona. The data indicate that the enclosed mass within radius R increases like M(R) ≈ R(kpc) × 1010M⊙, out to a radius of more than 100 kpc. The total galactic mass is at least 12 × 1011M⊙.

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.

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