Properties of Dark Matter Halos in Disk Galaxies

Jong, Roelof S. de; Kassin, Susan; Bell, Eric F.; Courteau, Stéphane

doi:10.1017/s0074180900183391

Cited by 3 publications

(3 citation statements)

References 18 publications

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“…When this effect is taken into account in the Cole et al (2000) model, the TF relation is no longer reproduced. Similar conclusions had been drawn from hydrodynamical simulations of galaxy formation by Navarro & Steinmetz (2000) and Eke, Navarro & Steinmetz (2001), and also from the analysis of de Jong et al (2004).…”

Section: The Tully–fisher Relationsupporting

confidence: 79%

Galaxy groups in the 2dF Galaxy Redshift Survey: the number density of groups

Eke

Baugh

Cole

et al. 2006

Monthly Notices of the Royal Astronomical Society

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The abundance of galaxy clusters as a function of mass is determined from the 2dF Galaxy Redshift Survey (2dFGRS) Percolation‐Inferred Galaxy Group (2PIGG) catalogue. This is used to estimate the amplitude of the matter fluctuation spectrum, parametrized by the linear theory rms density fluctuations in spheres of radius 8h−1 Mpc, σ8. The best‐fitting value for this parameter is highly correlated with the mean matter density in the Universe, Ωm, and is found to satisfy σ8= 0.25 Ω −0.92‐4.5(Ω m−0.22) 2m± 10 per cent (statistical) ±20 per cent (systematic) for 0.18 ≤Ωm≤ 0.50, assuming that Ωm+ΩΛ= 1. This gives σ8= 0.89 when evaluated at Ωm= 0.25. A ∼20 per cent correction has been applied to undo the systematic bias inherent in the measurement procedure. Mock catalogues, constructed from large cosmological N‐body simulations, are used to help understand and model these systematic errors. The abundance of galaxy groups as a function of group bJ‐band luminosity is also determined. This is used in conjunction with the halo mass function, determined from simulations, to infer the variation of halo mass‐to‐light ratio over four orders of magnitude in halo mass. The mass‐to‐light ratio shows a minimum value of 100 h M⊙/L⊙ in the bJ band at a total group luminosity of L italicb J≈ 5×109 h−2 L⊙. Together with the observed Tully–Fisher (TF) relation, this implies that the observed rotation speed of TF galaxies with L italicb J≤ 1010 h−2 L⊙ is within ∼10 per cent of the typical circular speed of the haloes that host them.

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Section: The Tully–fisher Relationsupporting

confidence: 79%

Galaxy groups in the 2dF Galaxy Redshift Survey: the number density of groups

Eke

Baugh

Cole

et al. 2006

Monthly Notices of the Royal Astronomical Society

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“…If major mergers produce a significant increase in the specific angular momentum of the dark matter haloes at large radii (Vitvitska et al 2002), minor mergers seem to just preserve or only slightly increase it with time (D'Onghia & Burkert 2004). But little is known about the expected distribution of the angular momentum of the baryons (van den Bosch et al 2002; de Jong et al 2004a), and even less if we focus on the central regions of galaxies (within a few effective radii). In fact, discs formed in numerical simulations are generally an order of magnitude too small (but see Dutton et al 2007, for a possible solution).…”

Section: Discussionmentioning

confidence: 99%

“…B/T is, however, a fairly difficult quantity to measure in early‐type galaxies, as it depends on the adopted model for the surface brightness distribution of the disc and bulge components. As emphasized by de Jong et al (2004a), the kinematic information is critical in assessing the rotational support of both components.…”

Section: Other Classificationsmentioning

confidence: 99%

The SAURON project - IX. A kinematic classification for early-type galaxies

Emsellem

Cappellari

Krajnović

et al. 2007

Monthly Notices of the Royal Astronomical Society

686

578

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Two-dimensional stellar kinematics of 48 representative elliptical (E) and lenticular (S0) galaxies obtained with the SAURON integral-field spectrograph reveal that early-type galaxies appear in two broad flavours, depending on whether they exhibit clear large-scale rotation or not. We define a new parameter λ R ≡ R |V | / R √ V 2 + σ 2 , which involves luminosityweighted averages over the full two-dimensional kinematic field as a proxy to quantify the observed projected stellar angular momentum per unit mass. We use it as a basis for a new kinematic classification: early-type galaxies are separated into slow and fast rotators, depending on whether they have λ R values within their effective radius R e below or above 0.1, respectively. Slow and fast rotators are shown to be physically distinct classes of galaxies, a result which cannot simply be the consequence of a biased viewing angle. Fast rotators tend to be relatively low-luminosity galaxies with M B −20.5. Slow rotators tend to be brighter and more massive galaxies, but are still spread over a wide range of absolute magnitude. Three slow rotators of our sample, among the most massive ones, are consistent with zero rotation. Remarkably, all other slow rotators (besides the atypical case of NGC 4550) contain a large kpc-scale kinematically decoupled core (KDC). All fast rotators (except one galaxy with well-known irregular shells) show well-aligned photometric and kinemetric axes, and small velocity twists, in contrast with most slow rotators which exhibit significant misalignments and velocity twists. These results are supported by a supplement of 18 additional early-type galaxies observed with SAURON. In a companion paper (Paper X), we also show that fast and slow rotators are distinct classes in terms of their orbital distribution. We suggest that gas is a key ingredient in the formation and evolution of fast rotators, and that the slowest rotators are the extreme evolutionary end point reached deep in gravitational potential wells where dissipationless mergers had a major role in the evolution, and for which most of the baryonic angular momentum was expelled outwards. Detailed numerical simulations in a cosmological context are required to understand how to form large-scale KDCs within slow rotators, and Ground-based photometric MDM Observatory data (Falcón-Barroso et al., in preparation) were obtained for all galaxies of the SAURON sample. We also made use of additional Hubble Space Telescope Wide Field Planetary Camera 2 (HST/WPFC2) data which are available for 42 galaxies out of the 48 E/S0. SAURONreconstructed images were used as well to directly derive a global

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Fast and slow rotators: the build-up of the red sequence

et al. 2007

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Abstract. Using the unique dataset obtained within the course of the SAURON project, a radically new view of the structure, dynamics and stellar populations of early-type galaxies has emerged. We show that galaxies come in two broad flavours (slow and fast rotators), depending on whether or not they exhibit clear large-scale rotation, as indicated via a robust measure of the specific angular momentum of baryons. This property is also linked with other physical characteristics of early-type galaxies, such as: the presence of dynamically decoupled cores, orbital structure and anisotropy, stellar populations and dark matter content. I here report on the observed link between this baryonic angular momentum and a mass sequence, and how this uniquely relates to the building of the red sequence via dissipative/dissipationless mergers and secular evolution.

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Properties of Dark Matter Halos in Disk Galaxies

Cited by 3 publications

References 18 publications

Galaxy groups in the 2dF Galaxy Redshift Survey: the number density of groups

Galaxy groups in the 2dF Galaxy Redshift Survey: the number density of groups

The SAURON project - IX. A kinematic classification for early-type galaxies

Fast and slow rotators: the build-up of the red sequence

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