Merger histories in warm dark matter structure formation scenarios

Knebe, Alexander; Devriendt, Julien; Mahmood, Asim; Silk, Joseph

doi:10.1046/j.1365-8711.2002.05017.x

Cited by 83 publications

(108 citation statements)

References 49 publications

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“…Numerical simulations of structure formation indicate that the differences between WDM and CDM models are most pronounced on small scales and in under-dense regions (e.g., Bode et al 2001;Knebe et al 2002Knebe et al , 2003Angulo et al 2013). Anticipating that these differences may in turn influence the properties of galaxies in such regions, we explore voids in the distribution of galaxies, and analogues of the Local Volume and the Local Void in our models.…”

Section: Galaxy Populations In Voids and In The Local Volumementioning

confidence: 99%

The galaxy population in cold and warm dark matter cosmologies

Wang

González-Pérez²,

Xie

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We use a pair of high resolution N-body simulations implementing two dark matter models, namely the standard cold dark matter (CDM) cosmogony and a warm dark matter (WDM) alternative where the dark matter particle is a 1.5 keV thermal relic. We combine these simulations with the GALFORM semi-analytical galaxy formation model in order to explore differences between the resulting galaxy populations. We use GALFORM model variants for CDM and WDM that result in the same z = 0 galaxy stellar mass function by construction. We find that most of the studied galaxy properties have the same values in these two models, indicating that both dark matter scenarios match current observational data equally well. Even in under-dense regions, where discrepancies in structure formation between CDM and WDM are expected to be most pronounced, the galaxy properties are only slightly different. The only significant difference in the local universe we find is in the galaxy populations of "Local Volumes", regions of radius 1 to 8Mpc around simulated Milky Way analogues. In such regions our WDM model provides a better match to observed local galaxy number counts and is five times more likely than the CDM model to predict subregions within them that are as empty as the observed Local Void. Thus, a highly complete census of the Local Volume and future surveys of void regions could provide constraints on the nature of dark matter.

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Section: Galaxy Populations In Voids and In The Local Volumementioning

confidence: 99%

The galaxy population in cold and warm dark matter cosmologies

Wang

González-Pérez²,

Xie

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…One possibility to reduce this power is to introduce Warm Dark Matter (i.e. Knebe et al 2002;Bode, Ostriker & Turok 2001;Avila-Reese et al 2001;Colin et al 2000). But another way to decrease power on a certain scale is to introduce a negative feature ("dip") into an otherwise unperturbed CDM power spectrum (cf.…”

Section: The Setupmentioning

confidence: 99%

Non-Standard Structure Formation Scenarios

Knebe¹,

Little²,

Islam³

et al. 2003

The Evolution of Galaxies

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Abstract. Observations on galactic scales seem to be in contradiction with recent high resolution N -body simulations. This so-called cold dark matter (CDM) crisis has been addressed in several ways, ranging from a change in fundamental physics by introducing self-interacting cold dark matter particles to a tuning of complex astrophysical processes such as global and/or local feedback. All these efforts attempt to soften density profiles and reduce the abundance of satellites in simulated galaxy halos. In this contribution we are exploring the differences between a Warm Dark Matter model and a CDM model where the power on a certain scale is reduced by introducing a narrow negative feature ("dip"). This dip is placed in a way so as to mimic the loss of power in the WDM model: both models have the same integrated power out to the scale where the power of the Dip model rises to the level of the unperturbed CDM spectrum again. Using N -body simulations we show that that the new Dip model appears to be a viable alternative to WDM while being based on different physics: where WDM requires the introduction of a new particle species the Dip stems from a non-standard inflationary period. If we are looking for an alternative to the currently challenged standard ΛCDM structure formation scenario, neither the ΛWDM nor the new Dip model can be ruled out with respect to the analysis presented in this contribution. They both make very similar predictions and the degeneracy between them can only be broken with observations yet to come.

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“…Dalcanton & Hogan 2001, Colin et al 2008. Several works have dealt with the effect of Warm Dark Matter (WDM) on halo structure (Bode et al 2001, Avila-Reese et al 2001, Knebe et al 2002, Tikhonov et al 2009, Schneider et al 2012. Constraints on the mass of a possible WDM candidate can be obtained from the analysis of the matter power spectrum from the Lyman-α forest (Seljak et al 2006, Viel et al 2005, Boyarsky et al 2009), current measurements suggest the WDM mass (for a pure thermal candidate) to be around (or above) 3.5 keV (Viel et al 2013, Polisensky & Ricotti 2014.…”

Section: Introductionmentioning

confidence: 99%

Strongly coupled dark energy cosmologies: preserving ΛCDM success and easing low-scale problems – II. Cosmological simulations

Macciò

Mainini

Penzo

et al. 2015

Mon. Not. R. Astron. Soc.

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In this second paper we present the first Nbody cosmological simulations of strongly coupled Dark Energy models (SCDEW), a class of models that alleviates theoretical issues related to the nature of dark energy. SCDEW models assume a strong coupling between Dark Energy (DE) and an ancillary Cold Dark Matter (CDM) component together with the presence of an uncoupled Warm Dark Matter component. The strong coupling between CDM and DE allows us to preserve small scale fluctuations even if the warm particle is quite light (≈ 100 eV). Our large scale simulations show that, for 10 11 < M/M ⊙ < 10 14 , SCDEW haloes exhibit a number density and distribution similar to a standard Lambda Cold Dark Matter (ΛCDM) model, even though they have lower concentration parameters. High resolution simulation of a galactic halo (M ∼ 10 12 M ⊙ ) shows ∼ 60% less substructures than its ΛCDM counterpart, but the same cuspy density profile. On the scale of galactic satellites (M ∼ 10 9 M ⊙ ) SCDEW haloes dramatically differ from ΛCDM . Due to the high thermal velocities of the WDM component they are almost devoid of any substructures and present strongly cored dark matter density profiles. These density cores extend for several hundreds of parsecs, in very good agreement with Milky Way satellites observations. Strongly coupled models, thanks to their ability to match observations on both large and small scales might represent a valid alternative to a simple ΛCDM model.

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Merger histories in warm dark matter structure formation scenarios

Cited by 83 publications

References 49 publications

The galaxy population in cold and warm dark matter cosmologies

The galaxy population in cold and warm dark matter cosmologies

Non-Standard Structure Formation Scenarios

Strongly coupled dark energy cosmologies: preserving ΛCDM success and easing low-scale problems – II. Cosmological simulations

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