We present the results of medium-resolution spectroscopy of 28 globular clusters (GCs) in six nearby galaxies of different luminosities and morphological types, situated in: M33 (15 objects), M31 (3), IC10 (4), UGCA86 (4), HolmbergIX (1), and DDO71 (1) obtained at the Special Astrophysical Observatory 6-meter telescope. Measurements of Lick absorption-line indices and comparison with SSP models enabled us to obtain their spectroscopic ages, metallicities and alpha-element to Fe abundance ratios. We found that all old and intermediate-age GCs in our sample have low metallicities [Z/H] < -0.8 dex. Metal-rich clusters are young and are preferentially found in galaxies more massive than ~10^9 M_sun. The least massive dwarfs of our sample, DDO71 and HolmbergIX, host one massive intermediate-age and one massive young metal-poor GC, respectively. [a/Fe] abundance ratios tend to be enhanced but closer to solar values for dwarf galaxies compared to GCs in more massive galaxies. We analyse the age-metallicity relation for GCs in our galaxy sample and others from the literature, and find, that 1) there is a general trend for GCs in low surface brightness dwarf galaxies to be more metal-poor at a given age than GCs in more massive galaxies; 2) the GC metallicity spread is wider for more massive galaxies; 3) intermediate-age GCs in early-type dwarf galaxies are more metal-rich at any given age than those in irregular galaxies of similar luminosity.
High mass galaxies, with halo masses $M_{200} \ge 10^{10} M_{\odot}$, reveal a remarkable near-linear relation between their globular cluster (GC) system mass and their host galaxy halo mass. Extending this relation to the mass range of dwarf galaxies has been problematic due to the difficulty in measuring independent halo masses. Here we derive new halo masses based on stellar and HI gas kinematics for a sample of nearby dwarf galaxies with GC systems. We find that the GC system mass--halo mass relation for galaxies populated by GCs holds from halo masses of $M_{200} \sim 10^{14} M_{\odot}$ d…
The sizes of entire systems of globular clusters (GCs) depend on the formation and destruction histories of the GCs themselves, but also on the assembly, merger and accretion history of the dark matter (DM) haloes that they inhabit. Recent work has shown a linear relation between total mass of globular clusters in the globular cluster system and the mass of its host dark matter halo, calibrated from weak lensing. Here we extend this to GC system sizes, by studying the radial density profiles of GCs around galaxies in nearby galaxy groups. We find that radial density profiles of the GC systems …
