The Centaurus Group and the Outer Halo of NGC 5128: Are they Dynamically Connected?

Abstract

NGC 5128, a giant elliptical galaxy only $\sim 4$ Mpc away, is the dominant member of a galaxy group of over 80 probable members. The Centaurus group provides an excellent sample for a kinematic comparison between the halo of NGC 5128 and its surrounding satellite galaxies. A new study, presented here, shows no kinematic difference in rotation amplitude, rotation axis, and velocity dispersion between the halo of NGC 5128, determined from over $\sim 340$ of its globular clusters, and those of the Centaurus group as a whole. These results suggest NGC 5128 could be behaving in part as the inner component to the galaxy group, and could have begun as a large initial seed galaxy, gradually built up by minor mergers and satellite accretions, consistent with simple cold dark matter models. The mass and mass-to-light ratios in the B-band, corrected for projection effects, are determined to be $(1.3\pm 0.5)\times 10^{12}$ M$_{\sun}$ and $52\pm 22$ M$_{\sun}$/L$_{\sun}$ for NGC 5128 out to a galactocentric radius of 45 kpc, and $(9.2\pm 3.0)\times 10^{12}$ M$_{\sun}$ and $153\pm 50$ M$_{\sun}$/L$_{\sun}$ for the Centaurus group, consistent with previous studies.

arXiv comment14 pages, 3 tables, 7 figures, Accepted for publication in AJ

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Cited by in corpus (23)

• The Hubble flow around the CenA / M83 galaxy complex
• A whirling plane of satellite galaxies around Centaurus A challenges cold dark matter cosmology
• Structural parameters for globular clusters in M31 and generalizations for the fundamental plane
• The Local Volume HI Survey (LVHIS)
• The dwarf galaxy satellite system of Centaurus A
• The Leo Elliptical NGC 3379: A Metal-Poor Halo Emerges
• The Kinematics of the Globular Cluster System of NGC 5128 with a New, Large Sample of Radial Velocity Measurements
• The Kinematics and Dynamics of the Globular Clusters and the Planetary Nebulae of NGC 5128
• How old are the stars in the halo of NGC 5128 (Centaurus A)?
• Luminosity Functions and Host-to-Host Scatter of Dwarf Satellite Systems in the Local Volume
• Symphony: Cosmological Zoom-in Simulation Suites over Four Decades of Host Halo Mass
• Metal-poor nuclear star clusters in two dwarf galaxies near Centaurus A suggesting formation from the in-spiraling of globular clusters
• Dynamics of Nearby Groups of Galaxies: the role of the cosmological constant
• Tracing the outer halo in a giant elliptical to 25 Reff
• A Recent Major Merger Tale for the Closest Giant Elliptical Galaxy Centaurus A
• The Survey of Centaurus A's Baryonic Structures (SCABS). II. The Extended Globular Cluster System of NGC5128 and its Nearby Environment
• CANGAROO-III Search for Gamma Rays from Centaurus A and the $\omega$ Centauri Region
• The ACS Virgo Cluster Survey. XVII. The Spatial Alignment of Globular Cluster Systems With Early-Type Host Galaxies
• Probing the Intermediate-Age Globular Clusters in NGC 5128 from Ultraviolet Observations
• The Light Element Abundance Distribution in NGC 5128 from Planetary Nebulae
• Improved Lemaitre-Tolman model and the mass and turn-around radius in group of galaxies
• The Cen A galaxy group: dynamical mass and missing baryons
• The Metallicity Distribution Function in Outer Halo Fields of Simulated Elliptical Galaxies Compared to Observations of NGC 5128