On the Formation and Evolution of Disk Galaxies: Cosmological Initial Conditions and the Gravitational Collapse

Avila-Reese, Vladimir; Firmani, C.; Hernández, X.

doi:10.1086/306136

Cited by 193 publications

(261 citation statements)

References 75 publications

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“…Numerous authors have emphasized the effect of an isotropic velocity dispersion (thus of non-radial motion) in the core of collisionless haloes. One common result of the previous studies (RG87 ;White & Zaritsky 1992;Avila-Reese et al 1998;Hiotelis 2002;Nusser 2001;Le Delliou & Enriksen 2003;Ascasibar et al 2004;Williams et al 2004) is that a larger amount of angular momentum leads to shallower final density profiles in the inner region of the halo. Moreover, baryons have been invoked both to shallow (El-Zant et al 2001, hereafter EZ01, 2003Romano-Diaz et al 2008) and to steepen (Blumenthal et al 1986) the dark matter profile.…”

Section: Introductionmentioning

confidence: 94%

“…Self-similar solutions were found by Fillmore & Goldreich (1984) and Bertschinger (1985), while Hoffman & Shaham (1985, hereafter HS) studied density profiles around density peaks. More recently, modifications of the self-similar collapse model to include more realistic dynamics of the growth process have been proposed (e.g., Avila-Reese et al 1998;Nusser & Sheth 1999;Henriksen & Widrow 1999;Subramanian et al 2000;Del Popolo et al 2000, hereafter DP2000). Ryden & Gunn (1987, hereafter RG87) were the first to relax the assumption of purely radial self-similar collapse by including nonradial motions arising from secondary perturbations in the halo.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Density profiles of dark matter haloes on galactic and cluster scales

Popolo

Kroupa²

2009

A&A

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“…To study structure formation in the highly non-linear regime, it is very useful to work within the framework of the spherical collapse model, introduced by Gunn & Gott (1972) and extended in many following works (Fillmore & Goldreich 1984;Bertschinger 1985;Hoffman & Shaham 1985;Ryden & Gunn 1987;Avila-Reese et al 1998;Subramanian et al 2000;Ascasibar et al 2004;Mota & van de Bruck 2004;Williams et al 2004;Abramo et al 2007;Pace et al 2010Pace et al , 2014. According to the model, perturbations are considered as being spherically symmetric non-rotating objects that, being overdense, decouple from the background Hubble expansion, reach a point of maximum expansion (turn-around) and collapse (formally to a singularity).…”

Section: Introductionmentioning

confidence: 99%

Effects of shear and rotation on the spherical collapse model for clustering dark energy

Pace¹,

Batista²,

Popolo³

2014

Monthly Notices of the Royal Astronomical Society

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In the framework of the spherical collapse model we study the influence of shear and rotation terms for dark matter fluid in clustering dark energy models. We evaluate, for different equations of state, the effects of these terms on the linear overdensity threshold parameter, δ c , and on the virial overdensity, ∆ V . The evaluation of their effects on δ c allows us to infer the modifications occurring on the mass function. Due to ambiguities in the definition of the halo mass in the case of clustering dark energy, we consider two different situations: the first is the classical one where the mass is of the dark matter halo only, while the second one is given by the sum of the mass of dark matter and dark energy. As previously found, the spherical collapse model becomes mass dependant and the two additional terms oppose to the collapse of the perturbations, especially on galactic scales, with respect to the spherical non-rotating model, while on clusters scales the effects of shear and rotation become negligible. The values for δ c and ∆ V are higher than the standard spherical model. Regarding the effects of the additional non-linear terms on the mass function, we evaluate the number density of halos. As expected, major differences appear at high masses and redshifts. In particular, quintessence (phantom) models predict more (less) objects with respect to the ΛCDM model and the mass correction due to the contribution of the dark energy component has negligible effects on the overall number of structures.

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“…To study the non-linear evolution of cosmic structures a popular analytical model, the spherical collapse model, was first introduced by Gunn & Gott (1972) and extended and improved by several following works (Fillmore & Goldreich 1984;Bertschinger 1985;Hoffman & Shaham 1985;Ryden & Gunn 1987;Avila-Reese et al 1998;Subramanian et al 2000;Ascasibar et al 2004;Williams et al 2004). Recently the formalism of the spherical collapse model was extended to include shear and rotation (del Popolo et al 2013a,b,c) and non-minimally ⋆ malekjani@basu.ac.ir coupled models (Pace et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Evolution of spherical overdensities in holographic dark energy models

Naderi¹,

Malekjani²,

Pace³

2015

Monthly Notices of the Royal Astronomical Society

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In this work we investigate the spherical collapse model in flat FRW dark energy universes. We consider the Holographic Dark Energy (HDE) model as a dynamical dark energy scenario with a slowly time-varying equation-of-state (EoS) parameter w de in order to evaluate the effects of the dark energy component on structure formation in the universe. We first calculate the evolution of density perturbations in the linear regime for both phantom and quintessence behavior of the HDE model and compare the results with standard Einstein-de Sitter (EdS) and ΛCDM models. We then calculate the evolution of two characterizing parameters in the spherical collapse model, i.e., the linear density threshold δ c and the virial overdensity parameter ∆ vir . We show that in HDE cosmologies the growth factor g(a) and the linear overdensity parameter δ c fall behind the values for a ΛCDM universe while the virial overdensity ∆ vir is larger in HDE models than in the ΛCDM model. We also show that the ratio between the radius of the spherical perturbations at the virialization and turn-around time is smaller in HDE cosmologies than that predicted in a ΛCDM universe. Hence the growth of structures starts earlier in HDE models than in ΛCDM cosmologies and more concentrated objects can form in this case. It has been shown that the non-vanishing surface pressure leads to smaller virial radius and larger virial overdensity ∆ vir . We compare the predicted number of halos in HDE cosmologies and find out that in general this value is smaller than for ΛCDM models at higher redshifts and we compare different mass function prescriptions. Finally, we compare the results of the HDE models with observations.

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On the Formation and Evolution of Disk Galaxies: Cosmological Initial Conditions and the Gravitational Collapse

Cited by 193 publications

References 75 publications

Density profiles of dark matter haloes on galactic and cluster scales

Density profiles of dark matter haloes on galactic and cluster scales

Effects of shear and rotation on the spherical collapse model for clustering dark energy

Evolution of spherical overdensities in holographic dark energy models

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