Deriving the Mass Distribution of M87 from Globular Clusters

Wu, Xianghua; Tremaine, Scott

doi:10.1086/501515

Cited by 43 publications

(49 citation statements)

References 24 publications

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“…Murphy et al (2011) analysed 278 GCs up to 47 kpc (≈ 0.15 deg) by means of orbit-based methods, together with stellar kinematics for the starlight, as to infer the (total) mass profile over a wide radial range. The expected (total) mass at 2 32 kpc is ≈ 34% higher than the one reported in Wu & Tremaine (2006). Also, mass-estimates from X-rays are almost 50% lower than the ones inferred from GCs at small radii (Murphy et al 2011).…”

Section: M87 and Its Globular Clustersmentioning

confidence: 57%

“…Romanowsky & Kochanek (2001) studied a set of 200 GCs by means of S79 orbit modelling, finding evidence for a dark halo with density falling off more slowly than r −2 . Wu & Tremaine (2006) applied a S79 orbit-based analysis, with a power-law total density, to a sample of 161 GCs between ≈ 0.03 and 0.3 degrees. They found γ = 1.6 ± 0.4, although the likelihood has three peaks, one of which is almost at γ = 2.…”

Section: M87 and Its Globular Clustersmentioning

confidence: 99%

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Dynamical models of elliptical galaxies – II. M87 and its globular clusters

Agnello

Evans

Romanowsky

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We study the Globular Cluster (GC) system of the nearby elliptical galaxy M87 using the newly available dataset with accurate kinematics provided by Strader et al. (2011). We find evidence for three distinct sub-populations of GCs in terms of colours, kinematics and radial profiles. We show that a decomposition into three populations -blue, intermediate and red GCs -is statistically preferred to one with two or four populations. The existence of three components has been suggested before, but here we are able to identify them robustly and relate them to the stellar profile. We exploit the sub-populations to derive dynamical constraints on the mass and Dark Matter (DM) content of M87 out to ∼ 100 kpc. We deploy a class of global mass-estimators, developed in Paper I, obtaining mass measurements at different locations. The DM fraction in M87 changes from ≈0.2 at the effective radius of the stellar light (0.02• or 6 kpc) to ≈0.95 at the distance probed by the most extended, blue GCs (0.47• or 135 kpc).We supplement this analysis with virial decompositions, which exploit the dynamical model to produce a separation into multiple components. These yield the luminous mass as 5.511 M ⊙ and the dark matter within 135 kpc as 8.0The inner DM density behaves as ρ ∼ r −γ with γ ≈ 1.6. This is steeper than the cosmologically preferred cusp of ρ ∼ r −1 (Dubinski & Carlberg; Navarro, Frenk & White), and may provide evidence of dark matter contraction. Finally, we combine the GC separation into three sub-populations with the Jeans equations, obtaining information on the orbital structure of the GC system. The centrally concentrated red GCs exhibit tangential anisotropy, consistent with the depletion of radial orbits by tidal shredding. The most extended blue GCs have an isotropic velocity dispersion tensor in the central parts, which becomes more tangential moving outwards, consistent with adiabatic contraction of the DM halo.

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Section: M87 and Its Globular Clustersmentioning

confidence: 57%

Section: M87 and Its Globular Clustersmentioning

confidence: 99%

Dynamical models of elliptical galaxies – II. M87 and its globular clusters

Agnello

Evans

Romanowsky

et al. 2014

Monthly Notices of the Royal Astronomical Society

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“…The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The mass of M87 within 32 kpc is 2:4 AE 0:6 ð Þ; 10 12 M according to Wu & Tremaine ( 2006 ), and the mass of NGC 1399 within 50 kpc is %2:0 ; 10 12 M as found by Richtler et al ( 2004).…”

Section: Discussionmentioning

confidence: 68%

Internal Properties of Ultracompact Dwarf Galaxies in the Virgo Cluster

Evstigneeva¹,

Gregg²,

Drinkwater³

et al. 2007

148

267

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We present new imaging and spectroscopic observations of six ultracompact dwarf (UCD) galaxies in the Virgo Cluster, along with reanalyzed data for five Fornax Cluster UCDs. These are the most luminous UCDs: À14 mag < M V < À12 mag. Our Hubble Space Telescope imaging shows that most of the UCDs have shallow or steep cusps in their cores; only one UCD has a flat ''King'' core. None of the UCDs show tidal cutoffs down to our limiting surface brightness. Spectroscopic analysis shows that Virgo UCDs are old (older than 8 Gyr) and have metallicities in the range from ½Z /H ¼ À1:35 to +0.35 dex. Five Virgo UCDs have supersolar [/Fe] abundance ratios, and one Virgo UCD has a solar abundance ratio. The supersolar [/Fe] abundances are typical of old stellar populations found in globular clusters and elliptical galaxies. We find that Virgo UCDs have structural and dynamical properties similar to Fornax UCDs. The Virgo and Fornax UCDs all have masses %(2Y9) ; 10 7 M and mass-to-light ratios %(3Y5) M /L ;V . The dynamical mass-to-light ratios for Virgo UCDs are consistent with simple stellar population model predictions: the Virgo UCDs do not require dark matter to explain their mass-to-light ratios. We conclude that the internal properties of Virgo UCDs are consistent with them being the high-mass/high-luminosity extreme of known globular cluster populations. We refrain from any firm conclusions on Fornax UCD origins until accurate age, metallicity, and -abundance estimates are obtained for them. Some of our results, notably the fundamental plane projections, are consistent with the formation of UCDs by the simple removal of the halo from the nuclei of nucleated dwarf galaxies. However, the ages, metallicities, and abundances for Virgo UCDs are not consistent with this simple stripping model. It might be consistent with more sophisticated models of the stripping process that include the effects of gas removal on the chemical evolution of the nuclei.

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“…Globular clusters (GCs) are often used as tracers of the gravitational potentials of galaxies and galaxy clusters (e.g. Kissler‐Patig et al 1999; Côté et al 2003; Wu & Tremaine 2006; Quercellini, Amendola & Balbi 2008; Gebhardt & Thomas 2009). Although this has been applied to theoretical Galactic potentials (e.g.…”

Section: Introductionmentioning

confidence: 99%

Halo globular clusters observed with AAOmega: dark matter content, metallicity and tidal heating

Lane

Kiss

Lewis

et al. 2010

Monthly Notices of the Royal Astronomical Society

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Globular clusters (GCs) have proven to be essential to our understanding of many important astrophysical phenomena. Here, we analyse spectroscopic observations of 10 halo GCs to determine their dark matter (DM) content, their tidal heating by the Galactic disc and halo, describe their metallicities and the likelihood that Newtonian dynamics explains their kinematics. We analyse a large number of members in all clusters, allowing us to address all these issues together, and we have included NGC 288 and M30 to overlap with previous studies. We find that any flattening of the velocity dispersion profiles in the outer regions of our clusters can be explained by tidal heating. We also find that all our GCs have M/LV≲ 5, therefore, we infer the observed dynamics do not require DM, or a modification of gravity. We suggest that the lack of tidal heating signatures in distant clusters indicates the halo is not triaxial. The isothermal rotations of each cluster are measured, with M4 and NGC 288 exhibiting rotation at a level of 0.9 ± 0.1 km s−1 and 0.25 ± 0.15 km s−1, respectively. We also indirectly measure the tidal radius of NGC 6752, determining a more realistic figure for this cluster than current literature values. Lastly, an unresolved and intriguing puzzle is uncovered with regard to the cooling of the outer regions of all ten clusters.

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Deriving the Mass Distribution of M87 from Globular Clusters

Cited by 43 publications

References 24 publications

Dynamical models of elliptical galaxies – II. M87 and its globular clusters

Dynamical models of elliptical galaxies – II. M87 and its globular clusters

Internal Properties of Ultracompact Dwarf Galaxies in the Virgo Cluster

Halo globular clusters observed with AAOmega: dark matter content, metallicity and tidal heating

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