Angular Momentum Profiles of Warm Dark Matter Halos

Bullock, James S.; Kravtsov, and Andrey V.; Colín, Pedro

doi:10.1086/338863

Cited by 20 publications

(27 citation statements)

References 30 publications

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“…In this paper, we perform a series of very high resolution CDM and WDM N ‐body simulations with the specific aim of exploring the halo model ingredients in the ΛWDM scenario. Over the past decade, there have been a limited number of numerical simulation studies of non‐linear structure formation in the WDM model (Colombi, Dodelson & Widrow 1996; Moore et al 1999; Colín, Avila‐Reese & Valenzuela 2000; White & Croft 2000; Avila‐Reese et al 2001; Bode et al 2001; Bullock, Kravtsov & Colín 2002; Zentner & Bullock 2003; Colín, Valenzuela & Avila‐Reese 2008; Zavala et al 2009; Macciò & Fontanot 2010; Dunstan et al 2011; Lovell et al 2012; Viel et al 2011). In most of these previous studies, conclusions have been drawn from object‐by‐object comparison of a relatively small number of haloes simulated in boxes of typical size L = 25 h −1 Mpc.…”

Section: Introductionmentioning

confidence: 99%

Non-linear evolution of cosmological structures in warm dark matter models

Schneider

Smith

Macciò

et al. 2012

Monthly Notices of the Royal Astronomical Society

303

423

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The dark energy dominated warm dark matter (WDM) model is a promising alternative cosmological scenario. We explore large‐scale structure formation in this paradigm. We do this in two different ways: with the halo model approach and with the help of an ensemble of high‐resolution N‐body simulations. Combining these quasi‐independent approaches leads to a physical understanding of the important processes which shape the formation of structures. We take a detailed look at the halo mass function, the concentrations and the linear halo bias of WDM. In all cases we find interesting deviations with respect to cold dark matter (CDM). In particular, the concentration–mass relation displays a turnover for group scale dark matter haloes, for the case of WDM particles with masses of the order of mWDM∼ 0.25 keV. This may be interpreted as a hint for top–down structure formation on small scales. We implement our results into the halo model and find much better agreement with simulations. On small scales, the WDM halo model now performs as well as its CDM counterpart.

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Section: Introductionmentioning

confidence: 99%

Non-linear evolution of cosmological structures in warm dark matter models

Schneider

Smith

Macciò

et al. 2012

Monthly Notices of the Royal Astronomical Society

303

423

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“…Past research on the impact of the WDM hypothesis on the phenomenology of cosmic structures has primarily focused on small-scale phenomena [10,[28][29][30][31][32], although there are some notable studies of large-scale structures [23,33]. In short, these results show that halo abundances for masses below the free-streaming mass-scale are suppressed relative to CDM.…”

Section: Introductionmentioning

confidence: 99%

Testing the warm dark matter paradigm with large-scale structures

2011

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We explore the impact of a ΛWDM cosmological scenario on the clustering properties large-scale structure in the Universe. We do this by extending the halo model. The new development is that we consider two components to the mass density: one arising from mass in collapsed haloes, and the second from a smooth component of uncollapsed mass. Assuming that the nonlinear clustering of dark matter haloes can be understood, then from conservation arguments one can precisely calculate the clustering properties of the smooth component and its cross-correlation with haloes. We then explore how the three main ingredients of the halo calculations, the halo mass function, bias and density profiles are affected by WDM. We show that, relative to CDM, the halo mass function is suppressed by 50%, for masses ∼ 100 times the free-streaming mass-scale M fs . Consequently, the bias of low mass haloes can be boosted by as much as ∼ 20% for 0.25 keV WDM particles. Core densities of haloes will also be suppressed relative to the CDM case. We also examine the impact of relic thermal velocities on the density profiles, and find that these effects are constrained to scales r < 1 h −1 kpc, and hence of little importance for dark matter tests, owing to uncertainties in the baryonic physics. We use our modified halo model to calculate the non-linear matter power spectrum, and find that there is significant small-scale power in the model. However, relative to the CDM case the power is suppressed. The amount of suppression depends on the mass of the WDM particle, but can be of order 10% at k ∼ 1 h Mpc −1 for particles of mass 0.25 keV. We then calculate the expected signal and noise that our set of ΛWDM models would give for a future weak lensing mission. We show that the models should in principle be separable at high significance. Finally, using the Fisher matrix formalism we forecast the limit on the WDM particle mass for a future full-sky weak lensing mission like Euclid or LSST. With Planck priors and using only multipoles l < 5000, we find that a lower limit of 2.6 keV should be easily achievable.

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“…the axis ratios) have a weak dependence on mass and redshift (Bullock 2002; Kasun & Evrard 2005; Allgood et al 2006; Bett et al 2007). The spin parameter distribution is well described by a lognormal function which varies weakly with halo mass (Barnes & Efstathiou 1987; Warren et al 1992; Cole & Lacey 1996; Bullock, Kravtsov & Colín 2002; Bett et al 2007). Bullock et al (2001) also found that the cumulative mass distribution of specific angular momentum j is well fitted by a universal function.…”

Section: Introductionmentioning

confidence: 99%

Are mergers responsible for universal halo properties?

Wang

White

2009

Monthly Notices of the Royal Astronomical Society

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N-body simulations of Cold Dark Matter (CDM) have shown that, in this hierarchical structure formation model, dark matter halo properties, such as the density profile, the phase-space density profile, the distribution of axial ratio, the distribution of spin parameter, and the distribution of internal specific angular momentum follow `universal' laws or distributions. Here we study the properties of the first generation of haloes in a Hot Dark Matter (HDM) dominated universe, as an example of halo formation through monolithic collapse. We find all these universalities to be present in this case also. Halo density profiles are very well fit by the Navarro et al (1997) profile over two orders of magnitude in mass. The concentration parameter depends on mass as $c \propto M^{0.2}$,reversing the dependence found in a hierarchical CDM universe. However, the concentration-formation time relation is similar in the two cases: earlier forming haloes tend to be more concentrated than their later forming counterparts. Halo formation histories are also characterized by two phases in the HDM case: an early phase of rapid accretion followed by slower growth. Furthermore, there is no significant difference between the HDM and CDM cases concerning the statistics of other halo properties: the phase-space density profile; the velocity anisotropy profile; the distribution of shape parameters; the distribution of spin parameter, and the distribution of internal specific angular momentum are all similar in the two cases. Only substructure content differs dramatically. These results indicate that mergers do not play a pivotal role in establishing the universalities, thus contradicting models which explain them as consequences of mergers.Comment: 10 pages, 13 figures, submitted to MNRA

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Angular Momentum Profiles of Warm Dark Matter Halos

Cited by 20 publications

References 30 publications

Non-linear evolution of cosmological structures in warm dark matter models

Non-linear evolution of cosmological structures in warm dark matter models

Testing the warm dark matter paradigm with large-scale structures

Are mergers responsible for universal halo properties?

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