The Spatial Distribution of Globular Cluster Systems in Early Type Galaxies: Estimation Procedure and Catalog of Properties for Globular Cluster Systems Observed with Deep Imaging Surveys

TL;DR

This paper analyzes the spatial distribution of globular cluster systems in 118 early-type galaxies using deep imaging surveys, introducing a procedure to fit their distributions with Sersic functions and estimate properties like effective radii and total counts.

Contribution

It presents a new methodology for selecting GC candidates, fitting their spatial distributions with Sersic functions, and estimating background contamination, including handling neighboring galaxy effects.

Findings

Successfully fitted spatial distributions for 118 galaxies.

Identified bimodal color distributions and separated blue and red GCs.

Provided a catalog of GC properties including effective radii and total numbers.

Abstract

We present an analysis of the spatial distribution of globular cluster (GC) systems of 118 nearby early-type galaxies in the Next Generation Virgo Cluster Survey (NGVS) and Mass Assembly of early-Type GaLAxies with their fine Structures (MATLAS) survey programs, which both used MegaCam on the Canada-France-Hawaii Telescope. We describe the procedure used to select GC candidates and fit the spatial distributions of GCs to a two-dimensional S\'ersic function, which provides effective radii (half number radii) and S\'ersic indices, and estimate background contamination by adding a constant term to the S'ersic function. In cases where a neighboring galaxy affects the estimation of the GC spatial distribution in the target galaxy, we fit two 2D S\'ersic functions, simultaneously. We also investigate the color distributions of GCs in our sample by using Gaussian Mixture Modeling. For GC systems with bimodal color distributions, we divide the GCs into blue and red subgroups and fit their respective spatial distributions with S\'ersic functions. Finally, we measure the total number of GCs based on our fitted S\'ersic function, and calculate the GC specific frequency.