The dark matter density problem in massive disk galaxies

We discuss measurements of disk mass from non-circular streaming motions of gas in the barred galaxies NGC 3095 and NGC 4123. in these galaxies with strong shocks and non-circular motions, the inner regions must be disk-dominated to reproduce the shocks. This requires dark matter halos of low central density and low concentration, compared to LCDM halo predictions. in addition, the baryonic collapse to a disk should have compressed the halo and increased the dark matter density, which sharpens the disagreement. One possible resolution is a substantial amount of angular momentum transfer from disk to halo, but this is not particularly attractive nor elegant.

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Dark Matter Density in Disk Galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308027415 ◽

2008 ◽

Vol 4 (S254) ◽

pp. 73-84

Author(s):

J. A. Sellwood

Keyword(s):

Dark Matter ◽

Structure Formation ◽

Matter Density ◽

Disk Galaxies ◽

Dark Matter Halos ◽

Dynamical Friction ◽

Physical Processes ◽

Dark Matter Density ◽

Density Reduction ◽

Λcdm Model

AbstractI show that the predicted densities of the inner dark matter halos in ΛCDM models of structure formation appear to be higher than estimates from real galaxies and constraints from dynamical friction on bars. This inconsistency would not be a problem for the ΛCDM model if physical processes that are omitted in the collisionless collapse simulations were able to reduce the dark matter density in the inner halos. I review the mechanisms proposed to achieve the needed density reduction.

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Angular Momentum Transfer in Dark Matter Halos: Erasing the Cusp

The Astrophysical Journal ◽

10.1086/506431 ◽

2006 ◽

Vol 649 (2) ◽

pp. 591-598 ◽

Cited By ~ 109

Author(s):

C. Tonini ◽

A. Lapi ◽

P. Salucci

Keyword(s):

Dark Matter ◽

Angular Momentum ◽

Momentum Transfer ◽

Dark Matter Halos ◽

Angular Momentum Transfer

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The Angular Momentum Dichotomy

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314010400 ◽

2014 ◽

Vol 10 (S309) ◽

pp. 349-349

Author(s):

Adelheid Teklu ◽

Rhea-Silvia Remus ◽

Klaus Dolag ◽

Andreas Burkert

Keyword(s):

Dark Matter ◽

Angular Momentum ◽

Lognormal Distribution ◽

Spiral Galaxies ◽

Disk Galaxies ◽

Dark Matter Halos ◽

Central Galaxy ◽

Relative Angular Momentum ◽

Spin Parameter ◽

Spheroidal Galaxies

AbstractIn the context of the formation of spiral galaxies the evolution and distribution of the angular momentum of dark matter halos have been discussed for more than 20 years, especially the idea that the specific angular momentum of the halo can be estimated from the specific angular momentum of its disk (e.g. Fall & Efstathiou (1980), Fall (1983) and Mo et al. (1998)). We use a new set of hydrodynamic cosmological simulations called Magneticum Pathfinder which allow us to split the galaxies into spheroidal and disk galaxies via the circularity parameter ϵ, as commonly used (e.g. Scannapieco et al. (2008)). Here, we focus on the dimensionless spin parameter λ = J |E|1/2 / (G M5/2) (Peebles 1969, 1971), which is a measure of the rotation of the total halo and can be fitted by a lognormal distribution, e.g. Mo et al. (1998). The spin parameter allows one to compare the relative angular momentum of halos across different masses and different times. Fig. 1 reveals a dichotomy in the distribution of λ at all redshifts when the galaxies are split into spheroids (dashed) and disk galaxies (dash-dotted). The disk galaxies preferentially live in halos with slightly larger spin parameter compared to spheroidal galaxies. Thus, we see that the λ of the whole halo reflects the morphology of its central galaxy. For more details and a larger study of the angular momentum properties of disk and spheroidal galaxies, see Teklu et al. (in prep.).

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Dark matter density profile and galactic metric in Eddington-inspired Born–Infeld gravity

Modern Physics Letters A ◽

10.1142/s0217732314500497 ◽

2014 ◽

Vol 29 (09) ◽

pp. 1450049 ◽

Cited By ~ 30

Author(s):

Tiberiu Harko ◽

Francisco S. N. Lobo ◽

M. K. Mak ◽

Sergey V. Sushkov

Keyword(s):

Dark Matter ◽

Gravitational Field ◽

Density Profile ◽

Galactic Center ◽

Matter Density ◽

Dark Matter Halos ◽

Field Equations ◽

Metric Tensor ◽

Dark Matter Density ◽

Gravitational Field Equations

We consider the density profile of pressureless dark matter in Eddington-inspired Born–Infeld (EiBI) gravity. The gravitational field equations are investigated for a spherically symmetric dark matter galactic halo, by adopting a phenomenological tangential velocity profile for test particles moving in stable circular orbits around the galactic center. The density profile and the mass distribution, as well as the general form of the metric tensor is obtained by numerically integrating the gravitational field equations, and in an approximate analytical form by using the Newtonian limit of the theory. In the weak field limit, the dark matter density distribution is described by the Lane–Emden equation with polytropic index n = 1, and is nonsingular at the galactic center. The parameter κ of the theory is determined so that the theory could provide a realistic description of the dark matter halos. The gravitational properties of the dark matter halos are also briefly discussed in the Newtonian approximation.

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On the Mass Dependence of the Inner Slopes of Dark Matter Density Profiles

Open Astronomy ◽

10.1515/astro-2017-0172 ◽

2014 ◽

Vol 23 (1) ◽

Author(s):

A. Del Popolo

Keyword(s):

Dark Matter ◽

Matter Density ◽

Mass Dependence ◽

Analytic Model ◽

Dark Matter Halos ◽

Logarithmic Density ◽

Density Profiles ◽

Dark Matter Density

AbstractWe study through a semi-analytic model how the inner slopes of relaxed ΛCDM dark matter halos with and without baryons depend on the halo mass. We find that the inner logarithmic density slope, α ≡

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The Structure of Cold Dark Matter Halos

Symposium - International Astronomical Union ◽

10.1017/s0074180900232452 ◽

1996 ◽

Vol 171 ◽

pp. 255-258 ◽

Cited By ~ 1

Author(s):

Julio F. Navarro

Keyword(s):

Dark Matter ◽

Cold Dark Matter ◽

Large Range ◽

Disk Galaxies ◽

Dark Matter Halos ◽

Density Profiles ◽

Halo Structure ◽

Disk Rotation ◽

Disk Mass ◽

The Masses

High resolution N-body simulations show that the density profiles of dark matter halos formed in the standard CDM cosmogony can be fit accurately by scaling a simple “universal” profile. Regardless of their mass, halos are nearly isothermal over a large range in radius, but significantly shallower than r–2 near the center and steeper than r–2 in the outer regions. The characteristic overdensity of a halo correlates strongly with halo mass in a manner consistent with the mass dependence of the epoch of halo formation. Matching the shape of the rotation curves of disk galaxies with this halo structure requires (i) disk mass-to-light ratios to increase systematically with luminosity, (ii) halo circular velocities to be systematically lower than the disk rotation speed, and (iii) that the masses of halos surrounding bright galaxies depend only weakly on galaxy luminosity. This offers an attractive explanation for the puzzling lack of correlation between luminosity and dynamics in observed samples of binary galaxies and of satellite companions of bright spiral galaxies, suggesting that the structure of dark matter halos surrounding bright spirals is similar to that of cold dark matter halos.

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Constraints on the Clumpiness of Dark Matter Halos Through Heating of Disk Galaxies

EAS Publications Series ◽

10.1051/eas:2003136 ◽

2003 ◽

Vol 10 ◽

pp. 95-95

Author(s):

E. Ardi ◽

T. Tsuchiya ◽

A. Burkert

Keyword(s):

Dark Matter ◽

Disk Galaxies ◽

Dark Matter Halos

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Determining the local dark matter density with LAMOST data

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stw565 ◽

2016 ◽

Vol 458 (4) ◽

pp. 3839-3850 ◽

Cited By ~ 25

Author(s):

Qiran Xia ◽

Chao Liu ◽

Shude Mao ◽

Yingyi Song ◽

Lan Zhang ◽

...

Keyword(s):

Dark Matter ◽

Matter Density ◽

Dark Matter Density

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Rotation of Galaxy Dark Matter Halos

Proceedings of the International Astronomical Union ◽

10.1017/s1743921306005394 ◽

2006 ◽

Vol 2 (S235) ◽

pp. 104-104

Author(s):

Stéphane Herbert-Fort ◽

Dennis Zaritsky ◽

Yeun Jin Kim ◽

Jeremy Bailin ◽

James E. Taylor

Keyword(s):

Dark Matter ◽

Angular Momentum ◽

Numerical Simulations ◽

Galaxy Formation ◽

Spiral Galaxy ◽

Observational Studies ◽

Spiral Galaxies ◽

Satellite System ◽

Dark Matter Halos ◽

The Mean

AbstractThe degree to which outer dark matter halos of spiral galaxies rotate with the disk is sensitive to their accretion history and may be probed with associated satellite galaxies. We use the Steward Observatory Bok telescope to measure the sense of rotation of nearby isolated spirals and combine these data with those of their associated satellites (drawn from SDSS) to directly test predictions from numerical simulations. We aim to constrain models of galaxy formation by measuring the projected component of the halo angular momentum that is aligned with that of spiral galaxy disks, Jz. We find the mean bulk rotation of the ensemble satellite system to be co-rotating with the disk with a velocity of 22 ± 13 km/s, in general agreement with previous observational studies and suggesting that galaxy disks could be formed by halo baryons collapsing by a factor of ≈10. We also find a prograde satellite fraction of 51% and Jz, of the satellite system to be positively correlated with the disk, albeit at low significance (2655 ± 2232 kpc km/s).

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