Globular Cluster Systems in Dwarf Galaxies: Catalogs and Comparisons

The connection between a galaxy’s total globular cluster system (GCS) mass and its halo mass has been studied for decades and it has been found that galaxies at nearly all observed masses adhere to a linear scaling relation between these properties. However, while we have ample, homogeneous data for galaxies with halo masses Mh ≳ 1010 M⊙ the data available for low-mass galaxies are more sparse, and both GCS mass and halo mass estimates are determined using varying methodologies. This work compiles all available literature data for dwarf galaxies with confident stellar mass and globular cluster (GC) count estimates, and converts these estimates to GCS masses and peak halo masses using a standard conversion. This allows for a consistent comparison of these masses to be made and a complete study of the behaviour of the MGCS–Mh relation to be conducted. We compare the positions of classical dwarfs on the scaling relation to those of ultradiffuse galaxies and extremely low surface brightness galaxies and find that these nonclassical dwarfs have, on average, systematically higher GC specific frequencies. This also makes them, on average, systematically positively offset from the MGCS–Mh relation, driving much of the high-MGCS scatter observed.