Dark matter haloes within clusters

Ghigna, Sebastiano; Moore, Ben; Governato, Fabio; Lake, George; Quinn, Thomas; Stadel, Joachim

doi:10.1046/j.1365-8711.1998.01918.x

Cited by 472 publications

(651 citation statements)

References 15 publications

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“…(Merritt 1984;Ghigna et al 1998). The tidal effects are strongest near the cluster core radius and the approximation r tidal r peri σ halo /σ clus for the tidal radius is found to work well.…”

Section: Fig 14mentioning

confidence: 99%

The edge of the M 87 halo and the kinematics of the diffuse light in the Virgo cluster core

Doherty¹,

Arnaboldi²,

Das

et al. 2009

A&A

133

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Aims. We study the kinematics and dynamics of the extreme outer halo of M 87, the central galaxy in the Virgo cluster, and its transition to the intracluster light (ICL). Methods. We present high resolution FLAMES/VLT spectroscopy of intracluster planetary nebula (PN) candidates, targeting three new fields in the Virgo cluster core with surface brightness down to μ B = 28.5. Based on the projected phase space information (sky positions and line-of-sight velocities) we separate galaxy and cluster components in the confirmed PN sample. We then use the spherical Jeans equation and the total gravitational potential as traced by the X-ray emission to derive the orbital distribution in the outer stellar halo of M 87. We determine the luminosity-specific PN number for the M 87 halo and the ICL from the photometric PN catalogs and sampled luminosities, and discuss the origin of the ICL in Virgo based on its measured PN velocities. Results. We confirm a further 12 PNs in Virgo, five of which are bound to the halo of M 87, and the remainder are true intracluster planetary nebulas (ICPNs). The M 87 PNs are confined to the extended stellar envelope of M 87, within a projected radius of ∼160 kpc, while the ICPNs are scattered across the whole surveyed region between M 87 and M 86, supporting a truncation of M 87's luminous outer halo at a 2σ level. The line-of-sight velocity distribution of the M 87 PNs at projected radii of 60 kpc and 144 kpc shows (i) no evidence for rotation of the halo along the photometric major axis; and (ii) that the velocity dispersion decreases in the outer halo, down to σ last = 78 ± 25 km s −1 at 144 kpc. The Jeans model for the M 87 halo stars fits the observed line-of-sight velocity dispersion profile only if the stellar orbits are strongly radially anisotropic (β 0.4 at r 10 kpc increasing to 0.8 at the outer edge), and if additionally the stellar halo is truncated at 150 kpc average elliptical radius. The α-parameters for the M 87 halo and the ICL are in the range of values observed for old (>10 Gyr) stellar populations. Conclusions. Both the spatial segregation of the PNs at the systemic velocity of M 87 and the dynamical model support that the stellar halo of M 87 ends at ∼150 kpc. We discuss several possible explanations for the origin of this truncation but are unable to discriminate between them: tidal truncation following an earlier encounter of M 87 with another mass concentration in the Virgo core, possibly around M 84, early AGN feedback effects, and adiabatic contraction due to the cluster dark matter collapsing onto M 87. From the spatial and velocity distribution of the ICPNs we infer that M 87 and M 86 are falling towards each other and that we may be observing them just before the first close pass. The new PN data support the view that the core of the Virgo cluster is not yet virialized but is in an ongoing state of assembly, and that massive elliptical galaxies are important contributors to the ICL in the Virgo cluster.

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Section: Fig 14mentioning

confidence: 99%

The edge of the M 87 halo and the kinematics of the diffuse light in the Virgo cluster core

Doherty¹,

Arnaboldi²,

Das

et al. 2009

A&A

133

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“…Since this proposal was put forward, it has been established that typical orbits in N-body simulations of dark matter halos are rather elliptical (see, e.g., [32]) so that M (r) changes around the orbit and M (r)r is no longer an adiabatic invariant. It has therefore been pointed out by Gnedin et al [12] that the relation in Eq.…”

Section: Testing Adiabatic Contractionmentioning

confidence: 99%

Baryonic pinching of galactic dark matter halos

2006

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High resolution cosmological N-body simulations of four galaxy-scale dark matter halos are compared to corresponding N-body/hydrodynamical simulations containing dark matter, stars and gas. The simulations without baryons share features with others described in the literature in that the dark matter density slope continuously decreases towards the center, with a density ρDM ∝ r −1.3±0.2 , at about 1% of the virial radius for our Milky Way sized galaxies. The central cusps in the simulations which also contain baryons steepen significantly, to ρDM ∝ r −1.9±0.2 , with an indication of the inner logarithmic slope converging. Models of adiabatic contraction of dark matter halos due to the central build-up of stellar/gaseous galaxies are examined. The simplest and most commonly used model, by Blumenthal et al., is shown to overestimate the central dark matter density considerably. A modified model proposed by Gnedin et al. is tested and it is shown that while it is a considerable improvement it is not perfect. Moreover it is found that the contraction parameters in their model not only depend on the orbital structure of the dark-matter-only halos but also on the stellar feedback prescription which is most relevant for the baryonic distribution. Implications for dark matter annihilation at the galactic center are discussed and it is found that although our simulations show a considerable reduced halo contraction as compared to the Blumenthal et al. model, the fluxes from dark matter annihilation is still expected to be enhanced by at least a factor of a hundred as compared to dark-matter-only halos. Finally, it is shown that while dark-matter-only halos are typically prolate, the dark matter halos containing baryons are mildly oblate with minor-to-major axis ratios of c/a = 0.73 ± 0.11, with their flattening aligned with the central baryonic disks.

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“…Depending on the way the source is defined, subhalo finders can be broadly categorized into three types: configuration space finders that examine the spatial clustering of particles (e.g., Springel et al 2001; Knollmann & Knebe 2009;Ghigna et al 1998); phase space finders that con-sider clustering in both spatial and velocity space (e.g., Elahi et al 2011;Behroozi et al 2013;Maciejewski et al 2009); and tracking finders that build the source from past progenitors (Tormen et al 1998;Han et al 2012). It has been shown that configuration space finders suffer from a "blending" problem, the difficulty of resolving subhalos embedded in the inner high density region of the host halo due to spatial overlap (Muldrew et al 2011;Knebe et al 2011;Han et al 2012).…”

Section: Introductionmentioning

confidence: 99%

hbt+: an improved code for finding subhaloes and building merger trees in cosmological simulations

Han

Cole

Frenk

et al. 2017

Monthly Notices of the Royal Astronomical Society

129

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Dark matter subhalos are the remnants of (incomplete) halo mergers. Identifying them and establishing their evolutionary links in the form of merger trees is one of the most important applications of cosmological simulations. The Hierachical Bound-Tracing (hbt) code identifies halos as they form and tracks their evolution as they merge, simultaneously detecting subhalos and building their merger trees. Here we present a new implementation of this approach, hbt+, that is much faster, more user friendly, and more physically complete than the original code. Applying hbt+ to cosmological simulations we show that both the subhalo mass function and the peak-mass function are well fit by similar double-Schechter functions.The ratio between the two is highest at the high mass end, reflecting the resilience of massive subhalos that experience substantial dynamical friction but limited tidal stripping. The radial distribution of the most massive subhalos is more concentrated than the universal radial distribution of lower mass subhalos. Subhalo finders that work in configuration space tend to underestimate the masses of massive subhalos, an effect that is stronger in the host centre. This may explain, at least in part, the excess of massive subhalos in galaxy cluster centres inferred from recent lensing observations. We demonstrate that the peak-mass function is a powerful diagnostic of merger tree defects, and the merger trees constructed using hbt+ do not suffer from the missing or switched links that tend to afflict merger trees constructed from more conventional halo finders. We make the hbt+ code publicly available.

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Dark matter haloes within clusters

Cited by 472 publications

References 15 publications

The edge of the M 87 halo and the kinematics of the diffuse light in the Virgo cluster core

The edge of the M 87 halo and the kinematics of the diffuse light in the Virgo cluster core

Baryonic pinching of galactic dark matter halos

hbt+: an improved code for finding subhaloes and building merger trees in cosmological simulations

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