The dark matter distribution in disc galaxies

Borriello, A.; Salucci, Paolo

doi:10.1046/j.1365-8711.2001.04077.x

Cited by 327 publications

(297 citation statements)

References 40 publications

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“…Firstly, the universal cuspy halo density profiles Moore et al 1999;Fukushige & Makino 2001), while in agreement with observations of galaxy clusters, are in apparent Send offprint requests to: M. Samland, e-mail: samland@astro.unibas.ch disagreement with the flat dark matter density distributions inferred from observations in the centres of galaxies (Salucci & Burkert 2000;Blais-Ouellette et al 2001;Borriello & Salucci 2001;de Blok et al 2001). Secondly, the specific angular momenta and scale lengths of the disk galaxies in the cosmological simulations are too small compared to real galaxies (Navarro & Steinmetz 2000b).…”

Section: Introductionmentioning

confidence: 49%

The formation of a disk galaxy within a growing dark halo

Samland

Gerhard

2003

A&A

126

153

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Abstract. We present a dynamical model for the formation and evolution of a massive disk galaxy, within a growing dark halo whose mass evolves according to cosmological simulations of structure formation. The galactic evolution is simulated with a new three-dimensional chemo-dynamical code, including dark matter, stars and a multi-phase ISM. The simulations start at redshift z = 4.85 with a small dark halo in a ΛCDM universe and we follow the evolution until the present epoch. The energy release by massive stars and supernovae prevents a rapid collapse of the baryonic matter and delays the maximum star formation until redshift z ≈ 1. The metal enrichment history in this model is broadly consistent with the evolution of [Zn/H] in damped Lyα systems. The galaxy forms radially from inside-out and vertically from halo to disk. As a function of metallicity, we have described a sequence of populations, reminiscent of the extreme halo, inner halo, metal-poor thick disk, thick disk, thin disk and inner bulge in the Milky Way. The first galactic component that forms is the halo, followed by the bulge, the disk-halo transition region, and the disk. At redshift z ≈ 1, a bar begins to form which later turns into a triaxial bulge. Despite the still idealized model, the final galaxy resembles present-day disk galaxies in many aspects. The bulge in the model consists of at least two stellar subpopulations, an early collapse population and a population that formed later in the bar. The initial metallicity gradients in the disk are later smoothed out by large scale gas motions induced by the bar. There is a pronounced deficiency of low-metallicity disk stars due to pre-enrichment of the disk ISM with metal-rich gas from the bulge and inner disk ("G-dwarf problem"). The mean rotation and the distribution of orbital eccentricities for all stars as a function of metallicity are not very different from those observed in the solar neighbourhood, showing that early homogeneous collapse models are oversimplified. The approach presented here provides a detailed description of the formation and evolution of an isolated disk galaxy in a ΛCDM universe, yielding new information about the kinematical and chemical history of the stars and the interstellar medium, but also about the evolution of the luminosity, the colours and the morphology of disk galaxies with redshift.

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Section: Introductionmentioning

confidence: 49%

The formation of a disk galaxy within a growing dark halo

Samland

Gerhard

2003

A&A

126

153

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“…While numerical simulations universally produce a cuspy density profile, observed rotation curves of dwarf spiral and LSB galaxies seem to indicate that the shape of the density profile on small scales is significantly shallower than found in numerical simulations (Flores & Primak 1994;Moore 1994;Burkert 1995;Kravtsov et al 1998;Salucci & Burkert 2000;Borriello & Salucci 2001;de Blok et al 2001;de Blok & Bosma 2002;Marchesini et al 2002;. It seems that the data generally favor logarithmic density slopes close to 0.2 Spekkens et al 2005).…”

Section: Introductionmentioning

confidence: 81%

Density profiles of dark matter haloes on galactic and cluster scales

Popolo

Kroupa²

2009

A&A

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Aims. In the present paper, we improve the "extended secondary infall model" (ESIM) of Williams and collaborators to obtain further insights into the cusp/core problem. Methods. A secondary infall model close to the collapse reality is obtained by simultaneously taking into account effects that till now have been studied separately, namely ordered and random angular momentum, dynamical friction, and baryon adiabatic contraction. The model is applied to structures on galactic scales (normal and dwarf spiral galaxies) and on galaxy cluster scales. Results. Our results imply that angular momentum and dynamical friction are able, on galactic scales, of overcoming the competing effect of adiabatic contraction and eliminating the Cusp. The NFW profile is not the standard outcome of the model, and it can be recovered in our model only if the system consists entirely of dark matter and the magnitude of angular momentum and dynamical friction are lower than the values predicted by the model itself. Comparison of the rotation curves of LSB galaxies with the results of our model are in good agreement. On scales smaller than 10 11 h −1 M , the slope is α 0, and on cluster scales we observe a similar evolution in the dark matter density profile but in this case the density profile slope flattens to α 0.7 for a cluster of 10 14 h −1 M . The total mass profile differs from that of dark matter showing a central cusp that is reproduced by a NFW model.

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“…For disk galaxies, an opposite (negative) tilt M dyn / M 0:7 Ã YM 0:8 Ã ( % À0:2 to À0.3) is observed (see, e.g., Persic et al 1996b;Bell & de Jong 2001;Shen et al 2003;Courteau et al 2007): low-mass disks (and dwarf spheroidals) are the most dark matterYdominated systems ( Persic & Salucci 1988, 1990Persic et al 1996aPersic et al , 1996bBorriello & Salucci 2001). Such a scaling is expected if the properties of disks track those of their dark matter halos: lower mass halos are more compact (Neto et al 2007 and references therein), and it is also well established that lower mass disks experience less efficient star formation (Bell & de Jong 2000;Gallazzi et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Dissipation and the Fundamental Plane: Observational Tests

Hopkins

Cox

Hernquist

2008

Astrophysical Journal

128

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We develop observational tests of the idea that dissipation in gas-rich mergers produces the fundamental plane (FP) and related correlations obeyed by ellipticals. The FP ''tilt'' implies that lower mass ellipticals have a higher ratio of stellar to dark matter within their stellar effective radii. Models argue that mergers between more gas-rich (typically lower mass) disks yield larger mass fractions formed in compact starbursts, giving a smaller stellar R e and higher M Ã /M tot within that R e . Such starbursts leave a characteristic imprint in the surface brightness profile: a central excess above an outer profile established by the dissipationless violent relaxation of disk stars. In previous work, we developed empirical methods to decompose the observed profiles of ellipticals and robustly estimate the amount of dissipation in the original spheroid-forming merger(s). Applying this to a large sample of observed ellipticals, we test whether or not their location on the FP and its tilt are driven by dissipation. At fixed mass, ellipticals formed in more dissipational events are smaller and have higher M Ã /M tot . At fixed degree of dissipation, there is no tilt in the FP. We show that the dynamical mass estimator R e 2 /G is a good estimator of the true mass: the observed FP tilt cannot primarily owe to other forms of nonhomology. Removing the effects of dissipation, observed ellipticals obey the same FP correlations as disks: unusual progenitors are not required to make typical ellipticals. Dissipation appears to be both necessary and sufficient to explain the FP tilt.

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The dark matter distribution in disc galaxies

Cited by 327 publications

References 40 publications

The formation of a disk galaxy within a growing dark halo

The formation of a disk galaxy within a growing dark halo

Density profiles of dark matter haloes on galactic and cluster scales

Dissipation and the Fundamental Plane: Observational Tests

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