Keck Cosmic Web Imager (KCWI) Spectra of Globular Clusters and Ultra Compact Dwarfs in the Halo of M87

Abstract

Using the Keck Cosmic Web Imager we obtain spectra of several globular clusters (GCs), ultra compact dwarfs (UCDs) and the inner halo starlight of M87, at a similar projected galactocentric radius of $\sim$5 kpc. This enables us, for the first time, to apply the same stellar population analysis to the GCs, UCDs and starlight consistently to derive ages, metallicities and alpha-element abundances in M87. We find evidence for a dual stellar population in the M87 halo light, i.e an $\sim$80\% component by mass which is old and metal-rich and a $\sim$20\% component which is old but metal-poor. Two red GCs share similar stellar populations to the halo light suggesting they may have formed contemporaneously with the dominant halo component. Three UCDs, and one blue GC, have similar stellar populations, with younger mean ages, lower metallicities and near solar alpha-element abundances. Combined with literature data, our findings are consistent with the scenario that UCDs are the remnant nucleus of a stripped galaxy. We further investigate the discrepancy in the literature for M87's kinematics at large radii, favouring a declining velocity dispersion profile. This work has highlighted the need for more self-consistent studies of galaxy halos.

arXiv comment12 pages, 10 figures, accepted for publication in MNRAS

References in corpus (61)

• Parametric Recovery of Line-of-Sight Velocity Distributions from Absorption-Line Spectra of Galaxies via Penalized Likelihood
• A large stellar evolution database for population synthesis studies. I. Scaled solar models and isochrones
• Improving the full spectrum fitting method: accurate convolution with Gauss-Hermite functions
• The Photometric Performance and Calibration of the HST Advanced Camera For Surveys
• Tracing Galaxy Formation with Stellar Halos I: Methods
• The MUSE second-generation VLT instrument
• Stellar population models of Lick indices with variable element abundance ratios
• Evolutionary Stellar Population Synthesis with MILES. Part I: The Base Models and a New Line Index System
• The Two Phases of Galaxy Formation
• Extragalactic Globular Clusters and Galaxy Formation
• UV-extended E-MILES stellar population models: young components in massive early-type galaxies
• The SAURON project - III. Integral-field absorption-line kinematics of 48 elliptical and lenticular galaxies
• Evolutionary stellar population synthesis with MILES - II. Scaled-solar and α-enhanced models
• The SAURON project - XVII. Stellar population analysis of the absorption line strength maps of 48 early-type galaxies
• The origin of accreted stellar halo populations in the Milky Way using APOGEE, $\text{Gaia}$, and the EAGLE simulations
• A Supermassive Black Hole in an Ultracompact Dwarf Galaxy
• Compact Stellar Systems in the Fornax Cluster: Super-massive Star Clusters or Extremely Compact Dwarf Galaxies?
• The Ages and Abundances of the M87 Globular Clusters
• Galaxy threshing and the origin of ultra-compact dwarf galaxies in the Fornax cluster
• Galactic accretion and the outer structure of galaxies in the CDM model
• The Relationships Among Compact Stellar Systems: A Fresh View of Ultra Compact Dwarfs
• The AIMSS Project I: Bridging the Star Cluster - Galaxy Divide
• The SAGES Legacy Unifying Globulars and GalaxieS Survey (SLUGGS): Sample definition, methods, and initial results
• The SLUGGS Survey: Kinematics for over 2500 Globular Clusters in Twelve Early-type Galaxies
• Metal-rich, Metal-poor: Updated Stellar Population Models for Old Stellar Systems
• Strong Balmer lines in old stellar populations: No need for young ages in ellipticals?
• Halo Mass and Assembly History Exposed in the Faint Outskirts: the Stellar and Dark Matter Haloes of Illustris Galaxies
• Ultra compact dwarf galaxy formation by tidal stripping of nucleated dwarf galaxies
• The Inner Halo of M87: A First Direct View of the Red-Giant Population
• Galaxy Kinematics with VIRUS-P: The Dark Matter Halo of M87
• The central region of the Fornax cluster -- III. Dwarf galaxies, globular clusters, and cD halo - are there interrelations?
• The Baryonic Halos of Elliptical Galaxies: Radial Distribution of Globular Clusters and Diffuse Hot Gas
• The Next Generation Virgo Cluster Survey. VI. The Kinematics of Ultra-compact Dwarfs and Globular Clusters in M87
• The Connection between Globular Cluster Systems and the Host Galaxies
• Origins of ultra-diffuse galaxies in the Coma cluster II. Constraints from their stellar populations
• The Ubiquity and Dual Nature of Ultra Compact Dwarfs
• The Outer Stellar Halos of Galaxies: how Radial Merger Mass Deposition, Shells and Streams depend on Infall-Orbit Configurations
• The Fornax3D project: overall goals, galaxy sample, MUSE data analysis and initial results
• The MASSIVE Survey - VIII. Stellar Velocity Dispersion Profiles and Environmental Dependence of Early-Type Galaxies
• Ultra-diffuse and Ultra-compact Galaxies in the Frontier Fields Cluster Abell 2744
• The AIMSS Project III: The Stellar Populations of Compact Stellar Systems
• The SLUGGS Survey: stellar kinematics, kinemetry and trends at large radii in 25 early-type galaxies
• Metallicity gradients in the globular cluster systems of early-type galaxies: In-situ and accreted components?
• The Age, Metallicity and Alpha-Element Abundance of Galactic Globular Clusters from Single Stellar Population Models
• The SLUGGS Survey: stellar masses and effective radii of early-type galaxies from Spitzer Space Telescope 3.6$\mu$m imaging
• The Distribution of Ultra-Diffuse and Ultra-Compact Galaxies in the Frontier Fields
• A kinematically distinct core and minor-axis rotation: the MUSE perspective on M87
• Constraining ultra-compact dwarf galaxy formation with galaxy clusters in the local universe
• The chemical composition of Ultracompact Dwarf Galaxies in the Virgo and Fornax Clusters
• The AIMSS Project II: Dynamical-to-Stellar Mass Ratios Across the Star Cluster - Galaxy Divide
• Searches for Ultra-Compact Dwarf Galaxies in Galaxy Groups
• Compact Stellar Systems around NGC 1399
• Detection of a distinct metal-poor stellar halo in the early-type galaxy NGC 3115
• Nuclei of early-type dwarf galaxies: are they progenitors of UCDs?
• Stellar Population Properties of Ultracompact Dwarfs in M87: a Mass-metallicity Correlation Connecting Low-metallicity Globular Clusters and Compact Ellipticals
• How elevated is the dynamical-to-stellar mass ratio of the ultra-compact dwarf S999?
• A metal-poor ultra compact dwarf galaxy at a kiloparsec distance from the low-mass elliptical galaxy FCC47
• The Strikingly Metal-Rich Halo of the Sombrero Galaxy
• Is There a Fundamental Upper Limit to the Mass of a Star Cluster?
• An expanded catalogue of low surface brightness galaxies in the Coma cluster using Subaru/Suprime-Cam
• Spatially-resolved stellar populations and kinematics with KCWI: probing the assembly history of the massive early-type galaxy NGC 1407

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• Ultra-compact dwarfs beyond the centre of the Fornax galaxy cluster: Hints of UCD formation in low-density environments
• Signs of `Everything Everywhere All At Once' formation in low surface brightness globular cluster-rich dwarf galaxies
• Testing the tidal stripping scenario of ultra-compact dwarf galaxy formation by using internal properties
• The creation of a massive UCD by tidal threshing from NGC 936