New Constraints on a complex relation between globular cluster colors and environment

Abstract

We present an analysis of high-quality photometry for globular clusters (GCs) in the Virgo cluster core region, based on data from the Next Generation Virgo Cluster Survey (NGVS) pilot field, and in the Milky Way (MW) based on VLT/X-Shooter spectrophotometry. We find significant discrepancies in color-color diagrams between sub-samples from different environments, confirming that the environment has a strong influence on the integrated colors of GCs. GC color distributions along a single color are not sufficient to capture the differences we observe in color-color space. While the average photometric colors become bluer with increasing radial distance to the cD galaxy M87, we also find a relation between the environment and the slope and intercept of the color-color relations. A denser environment seems to produce a larger dynamic range in certain color indices. We argue that these results are not due solely to differential extinction, IMF variations, calibration uncertainties, or overall age/metallicity variations. We therefore suggest that the relation between the environment and GC colors is, at least in part, due to chemical abundance variations, which affect stellar spectra and stellar evolution tracks. Our results demonstrate that stellar population diagnostics derived from model predictions which are calibrated on one particular sample of GCs may not be appropriate for all extragalactic GCs. These results advocate a more complex model of the assembly history of GC systems in massive galaxies that goes beyond the simple bimodality found in previous decades.

7 pages, 5 figures, accepted for publication in ApJ-Letters

References in corpus (31)

• The propagation of uncertainties in stellar population synthesis modeling III: model calibration, comparison, and evaluation
• The Tenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Apache Point Observatory Galactic Evolution Experiment
• The ACS Virgo Cluster Survey. XIII. SBF Distance Catalog and the Three-Dimensional Structure of the Virgo Cluster
• The ACS Fornax Cluster Survey. V. Measurement and Recalibration of Surface Brightness Fluctuations and a Precise Value of the Fornax--Virgo Relative Distance
• The ACS Virgo Cluster Survey IX: The Color Distributions of Globular Cluster Systems in Early-Type Galaxies
• Stellar population models at high spectral resolution
• Evolutionary synthesis of galaxies at high spectral resolution with the code PEGASE-HR
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. V. Constraints on Formation Scenarios
• The ACS Virgo Cluster Survey X. Half-light Radii of Globular Clusters in Early-Type Galaxies: Environmental Dependencies and a Standard Ruler for Distance Estimation
• Wide-Field Precision Kinematics of the M87 Globular Cluster System
• The HST/ACS Coma Cluster Survey IV. Intergalactic Globular Clusters and the Massive Globular Cluster System at the Core of the Coma Galaxy Cluster
• Improved Photometric Calibration of the SNLS and the SDSS Supernova Surveys
• Galaxy Groups
• New Light on the Formation and Evolution of M31 and its Globular Cluster System
• The ACS Virgo Cluster Survey. XIV. Analysis of Color-Magnitude Relations in Globular Cluster Systems
• Flux calibration of medium-resolution spectra from 300 nm to 2500 nm: Model reference spectra and telluric correction
• The Next Generation Virgo Cluster Survey - Infrared (NGVS-IR): I. A new Near-UV/Optical/Near-IR Globular Cluster selection tool
• The Globular Cluster System in M87: A Wide-Field Study with CFHT/Megacam
• M31 Globular Cluster Abundances from High-Resolution, Integrated-Light Spectroscopy
• Synthetic photometry for M and K giants and stellar evolution: hydrostatic dust-free model atmospheres and chemical abundances
• The Next Generation Virgo Cluster Survey (NGVS). XIII. The Luminosity and Mass Function of Galaxies in the Core of the Virgo Cluster and the Contribution from Disrupted Satellites
• Stellar Population Models and Individual Element Abundances II: Stellar Spectra and Integrated Light Models
• The Detailed Chemical Properties of M31 Star Clusters I. Fe, Alpha and Light Elements
• Hot Populations in M87 Globular Clusters
• UV Bright Globular Clusters in M87: More Evidence for Super-helium-rich Stellar Populations?
• Wide-Field Hubble Space Telescope Observations of the Globular Cluster System in NGC1399
• Extremely alpha-Enriched Globular Clusters in Early-Type Galaxies: A Step towards the Dawn of Stellar Populations?
• The Panchromatic High-Resolution Spectroscopic Survey of Local Group Star Clusters - I. General Data Reduction Procedures for the VLT/X-shooter UVB and VIS arm
• UV Insights into the Complex Populations of M 87 Globular Clusters
• G2C2 II: Integrated colour-metallicity relations for Galactic Globular Clusters in SDSS passbands
• Galaxy structure from multiple tracers: I. A census of M87's globular cluster populations

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• The Color Gradients of the Globular Cluster Systems in M87 and M49
• Extragalactic globular cluster near-infrared spectroscopy: I. Integrated near-infrared spectra of Centaurus A/NGC 5128
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