Euclid preparation. LVIII. Detecting globular clusters in the Euclid survey

Abstract

Extragalactic globular clusters (EGCs) are an abundant and powerful tracer of galaxy dynamics and formation, and their own formation and evolution is also a matter of extensive debate. The compact nature of globular clusters means that they are hard to spatially resolve and thus study outside the Local Group. In this work we have examined how well EGCs will be detectable in images from the Euclid telescope, using both simulated pre-launch images and the first early-release observations of the Fornax galaxy cluster. The Euclid Wide Survey will provide high-spatial resolution VIS imaging in the broad IE band as well as near-infrared photometry (YE, JE, and HE). We estimate that the galaxies within 100 Mpc in the footprint of the Euclid survey host around 830 000 EGCs of which about 350 000 are within the survey's detection limits. For about half of these EGCs, three infrared colours will be available as well. For any galaxy within 50Mpc the brighter half of its GC luminosity function will be detectable by the Euclid Wide Survey. The detectability of EGCs is mainly driven by the residual surface brightness of their host galaxy. We find that an automated machine-learning EGC-classification method based on real Euclid data of the Fornax galaxy cluster provides an efficient method to generate high purity and high completeness GC candidate catalogues. We confirm that EGCs are spatially resolved compared to pure point sources in VIS images of Fornax. Our analysis of both simulated and first on-sky data show that Euclid will increase the number of GCs accessible with high-resolution imaging substantially compared to previous surveys, and will permit the study of GCs in the outskirts of their hosts. Euclid is unique in enabling systematic studies of EGCs in a spatially unbiased and homogeneous manner and is primed to improve our understanding of many understudied aspects of GC astrophysics.

Accepted in A&A

References in corpus (30)

• Euclid. I. Overview of the Euclid mission
• Updated Nearby Galaxy Catalog
• A Supermassive Black Hole in an Ultracompact Dwarf Galaxy
• Extensive Globular Cluster Systems Associated with Ultra Diffuse Galaxies in the Coma Cluster
• Euclid. III. The NISP Instrument
• Globular Cluster Systems in Nearby Dwarf Galaxies: I. HST/ACS Observations and Dynamical Properties of Globular Clusters at Low Environmental Density
• The outer halo globular cluster system of M31 - II. Kinematics
• Euclid. II. The VIS Instrument
• The Canada-France Imaging Survey: First results from the u-band component
• The SLUGGS survey: Exploring the metallicity gradients of nearby early-type galaxies to large radii
• On the Metallicity-Color Relations and Bimodal Color Distributions in Extragalactic Globular Cluster Systems
• Globular Cluster Metallicity Subpopulations in NGC 4472
• Implications for Galaxy Formation Models from Observations of Globular Clusters around Ultra-Diffuse Galaxies
• The Heraklion Extragalactic Catalogue (HECATE): a value-added galaxy catalogue for multi-messenger astrophysics
• Modelling simple stellar populations in the near-ultraviolet to near-infrared with the X-shooter Spectral Library (XSL)
• The Fornax Deep Survey with VST. IX. The catalog of sources in the FDS area, with an example study for globular clusters and background galaxies
• Euclid: Early Release Observations -- Dwarf galaxies in the Perseus galaxy cluster
• Globular clusters as tracers of the dark matter halo: insights from the E-MOSAICS simulations
• The Next Generation Virgo Cluster Survey (NGVS). XXXV. First Kinematical Clues of Overly-Massive Dark Matter Halos in Several Ultra-Diffuse Galaxies in the Virgo Cluster
• NGC 5128 globular cluster candidates out to 150 kpc: a comprehensive catalog from Gaia and ground based data
• A Photometric Survey of Globular Cluster Systems in Brightest Cluster Galaxies
• The Fornax Cluster VLT Spectroscopic Survey III -- Kinematical characterisation of globular clusters across the Fornax galaxy cluster
• Euclid: Early Release Observations -- Globular clusters in the Fornax galaxy cluster, from dwarf galaxies to the intracluster field
• New Constraints on a complex relation between globular cluster colors and environment
• Ultra-compact dwarfs beyond the centre of the Fornax galaxy cluster: Hints of UCD formation in low-density environments
• DDO216-A1: a central globular cluster in a low-luminosity transition type galaxy
• Multiple stellar populations in Asymptotic Giant Branch stars of Galactic Globular Clusters
• The faint globular cluster in the dwarf galaxy Andromeda I
• Euclid preparation: XLVIII. The pre-launch Science Ground Segment simulation framework
• Investigating the Dark Matter Halo of NGC 5128 using a Discrete Dynamical Model

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• Euclid: Early Release Observations of diffuse stellar structures and globular clusters as probes of the mass assembly of galaxies in the Dorado group
• The Next Generation Fornax Survey (NGFS).VIII. A Support Vector Machine Approach for Disentangling Globular Clusters from other Sources
• A Pearl in the Shell: an ultra-compact dwarf within the tidal debris surrounding spiral galaxy NGC 7531
• Fuzzy dark matter dynamical friction: stalling of globular clusters induced by dynamical heatings
• The contribution of the color space in LSST-like photometry for the selection of extragalactic globular cluster candidates