2023MNRAS.518.2453D

We present a post-processing catalogue of globular clusters (GCs) for the 39 most massive groups and clusters in the TNG50 simulation of the IlllustrisTNG project (virial masses $M_{200} =[5\times 10^{12} \rm {\!-\!} 2 \times 10^{14}$] M_⊙). We tag GC particles to all galaxies with stellar mass M_* ≥ 5 × 10⁶ M_⊙, and we calibrate their masses to reproduce the observed power-law relation between GC mass and halo mass for galaxies with M₂₀₀ ≥ 10¹¹ M_⊙ (corresponding to M_* ∼ 10⁹ M_⊙). Here, we explore whether an extrapolation of this M_GC-M₂₀₀ relation to lower mass dwarfs is consistent with current observations. We find a good agreement between our predicted number and specific frequency of GCs in dwarfs with $\rm {\it M}_*=[5 \times 10^6 \rm {\!-\!} 10^9]$ M_⊙ and observations. Moreover, we predict a steep decline in the GC occupation fraction for dwarfs with M_* < 10⁹ M_⊙ that agrees well with current observational constraints. This declining occupation fraction is due to a combination of tidal stripping in all dwarfs plus a stochastic sampling of the GC mass function for dwarfs with M_* < 10^7.5 M_⊙. Our simulations also reproduce available constraints on the abundance of intracluster GCs in Virgo and Centaurus A. These successes provide support to the hypothesis that the M_GC-M₂₀₀ relation holds, albeit with more scatter, all the way down to the regime of classical dwarf spheroidals in these environments. Our GC catalogues are publicly available as part of the IllustrisTNG data release.