Searching for globular clusters in the inner halo of the Circinus galaxy

Abstract

In this study, we search for Globular Clusters (GCs) in the inner halo of the Circinus galaxy using a combination of observational data. Our dataset includes observations from the VISTA Variables in the Vía Láctea Extended Survey (VVVX), optical data from Gaia Release 3 (DR3), and observations from the Dark Energy Camera (DECam). These multiple data sources provide a comprehensive basis for our analysis. Our search was concentrated within a 50 kpc radius from the centre, leading to the identification of 93 sources that met our established criteria. To ensure the reliability of our findings, we conducted multiple examinations for sample contamination. These examinations incorporated tests based on Gaia Astrometric Excess Noise (AEN), the Blue Photometer (BP)/Red Photometer (RP) Excess Factor (BRexcess), as well as comparisons with stellar population models. This analysis confidently classified 41 sources as genuine GCs, as they successfully passed both the 3$\sigma$ Gaia AEN and BRexcess tests. We used the ISHAPE program to determine the structural parameters (half-light radii) of the GC candidates, with a peak effective radius of 4$\pm$ 0.5 pc. The catalogue mainly consists of bright GCs. Relationships between colour, size, and distance were found in the GC candidates, alongside confirmation of bi-modality in colour distributions.

15 pages, 14 figures

References in corpus (11)

• The SAGES Legacy Unifying Globulars and GalaxieS Survey (SLUGGS): Sample definition, methods, and initial results
• A large stellar evolution database for population synthesis studies. IV. Integrated properties and spectra
• Globular Cluster Systems in Brightest Cluster Galaxies. III: Beyond Bimodality
• Global Properties of the Globular Cluster Systems of Four Spiral Galaxies
• Sizes of Confirmed Globular Clusters in NGC 5128: A Wide-Field High-Resolution Study
• Luminosity functions of globular clusters in five nearby spiral galaxies using HST/ACS images
• Searching for Extragalactic Sources in the VISTA Variables in the Vía Láctea Survey
• Low-Metallicity Globular Clusters in the Low-Mass Isolated Spiral Galaxy NGC 2403
• Gemini Spectra of Star Clusters in the Spiral Galaxy M101
• AGN candidates in the VVV near-IR galaxy catalogue
• The Ancient Globular Clusters of NGC 1291

Cited by in corpus (2)

• The VISTA Variables in the Vía Láctea eXtended (VVVX) ESO public survey: Completion of the observations and legacy
• Multi-Wavelength characterization of VVVX open clusters