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Full-Text Articles in Physical Sciences and Mathematics
Ultra Compact Dwarfs In The Core Of The Perseus Cluster: Ucd Formation Via Tidal Stripping, S. J. Penny, D. A. Forbes, J. Strader, C. Usher, J. P. Brodie, Aaron J. Romanowsky
Ultra Compact Dwarfs In The Core Of The Perseus Cluster: Ucd Formation Via Tidal Stripping, S. J. Penny, D. A. Forbes, J. Strader, C. Usher, J. P. Brodie, Aaron J. Romanowsky
Aaron J. Romanowsky
We present the results of a Keck/DEIMOS survey of Ultra Compact Dwarfs (UCDs) in the Perseus Cluster core. We confirm cluster membership for 14 UCDs, with radial velocities ~5300 km s−1. Two of these confirmed Perseus UCDs have extremely blue colours (B−R<0.6 mag), reside in star forming filaments surrounding NGC 1275, and have likely formed as massive star clusters in the last ~100 Myr. We also measure a central velocity dispersion of a third, UCD13 (σ0=38±8 km s−1), the most extended UCD in our sample. We determine it to have radius Re=85±1.1 pc, a dynamical mass of (2.3±0.8)×108 M⊙, and a metallicity [Z/H]=−0.52+0.33−0.29 dex. UCD13 and the cluster's central galaxy, NGC 1275, have a projected separation of 30 kpc and a radial velocity difference of ~20 km s−1. Based on its size, red colour, internal velocity dispersion, dynamical mass, metallicity and proximity to NGC 1275, we argue that UCD13 is likely the remnant nucleus of a tidally stripped dE, with this progenitor dE having MB≈−16 mag and mass ∼109 M⊙.
The Sluggs Survey: Breaking Degeneracies Between Dark Matter, Anisotropy And The Imf Using Globular Cluster Subpopulations In The Giant Elliptical Ngc 5846, N. R. Napolitano, V. Pota, Aaron J. Romanowsky, D. A. Forbes, J. P. Brodie, C. Foster
The Sluggs Survey: Breaking Degeneracies Between Dark Matter, Anisotropy And The Imf Using Globular Cluster Subpopulations In The Giant Elliptical Ngc 5846, N. R. Napolitano, V. Pota, Aaron J. Romanowsky, D. A. Forbes, J. P. Brodie, C. Foster
Aaron J. Romanowsky
We study the mass and anisotropy distribution of the giant elliptical galaxy NGC 5846 using stars, as well as the red and blue globular cluster (GC) subpopulations. We break degeneracies in the dynamical models by taking advantage of the different phase space distributions of the two GC subpopulations to unambiguously constrain the mass of the galaxy and the anisotropy of the GC system. Red GCs show the same spatial distribution and behaviour as the starlight, whereas blue GCs have a shallower density profile, a larger velocity dispersion and a lower kurtosis, all of which suggest a different orbital distribution. We …
Dynamical Models Of Elliptical Galaxies – Ii. M87 And Its Globular Clusters, A. Angello, N. W. Evans, Aaron J. Romanowsky, J. P. Brodie
Dynamical Models Of Elliptical Galaxies – Ii. M87 And Its Globular Clusters, A. Angello, N. W. Evans, Aaron J. Romanowsky, J. P. Brodie
Aaron J. Romanowsky
We study the Globular Cluster (GC) system of the nearby elliptical galaxy M87 using the newly available dataset with accurate kinematics (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, 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 use a class of global mass-estimators …
The Sluggs Survey: New Evidence For A Tidal Interaction Between The Early Type Galaxies Ngc 4365 And Ngc 4342, C. Blom, D. A. Forbes, C. Foster, Aaron J. Romanowsky, J. P. Brodie
The Sluggs Survey: New Evidence For A Tidal Interaction Between The Early Type Galaxies Ngc 4365 And Ngc 4342, C. Blom, D. A. Forbes, C. Foster, Aaron J. Romanowsky, J. P. Brodie
Aaron J. Romanowsky
We present new imaging and spectral data for globular clusters (GCs) around NGC 4365 and NGC 4342. NGC 4342 is a compact, X-ray luminous S0 galaxy with an unusually massive central black hole. NGC 4365 is another atypical galaxy that dominates the W' group of which NGC 4342 is a member. Using imaging from the MegaCam instrument on the Canada-France-Hawaii Telescope (CFHT) we identify a stream of GCs between the two galaxies and extending beyond NGC 4342. The stream of GCs is spatially coincident with a stream/plume of stars previously identified. We find that the photometric colours of the stream …