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Abstract We study the size and structure of globular cluster (GC) systems of 118 early-type galaxies from the NGVS, MATLAS, and ACSVCS surveys. Fitting Sérsic profiles, we investigate the relationship between effective radii of GC systems ( R e ,gc ) and galaxy properties. GC systems are 2–4 times more extended than host galaxies across the entire stellar mass range of our sample (10 8.3 M ⊙ ( g ′ − i ′ ) color (Δ gi ): GCs with similar colors to their hosts have a “red” Δ gi , and those significantly bluer GCs have a “blue” Δ gi . The GC populations with red Δ gi , even in dwarf galaxies, are twice as extended as the stars, suggesting that formation or survival mechanisms favor the outer regions. We find a tight correlation between R e ,gc and the total number of GCs, with intrinsic scatter ≲0.1 dex spanning two and three orders of magnitude in size and number, respectively. This holds for both red and blue subpopulations, albeit with different slopes. Assuming that N GC,Total correlates with M 200 , we find that the red GC systems have effective radii of roughly 1%–5% R 200 , while the blue GC systems in massive galaxies can have sizes as large as ∼10% R 200 . Environmental dependence on R e ,gc is also found, with lower-density environments exhibiting more extended GC systems at fixed mass.
Lim et al. (Wed,) studied this question.