The chemical composition of globular clusters in the Local Group
  We present detailed abundance measurements for 45 globular clusters (GCs) in
galaxies in (and, in one case, beyond) the Local Group. The measurements are
based on new high-resolution integrated-light spectra of GCs in NGC 185, NGC
205, M31, M33, and NGC 2403, combined with reanalysis of previous observations
of GCs in the Fornax dSph, WLM, NGC 147, NGC 6822, and the Milky Way. The GCs
cover the range -2.8 < [Fe/H] < -0.1 and we determined abundances for Fe, Na,
Mg, Si, Ca, Sc, Ti, Cr, Mn, Ni, Cu, Zn, Zr, Ba, and Eu. Corrections for non
local thermodynamic equilibrium effects are included for Na, Mg, Ca, Ti, Mn,
Fe, Ni, and Ba. For several of the galaxies, our measurements provide the first
quantitative constraints on the detailed composition of their metal-poor
stellar populations. Overall, the GCs in different galaxies exhibit remarkably
uniform abundance patterns of the alpha-, iron-peak, and neutron-capture
elements, with a dispersion of less than 0.1 dex in [alpha/Fe] for the full
sample. There is a hint that GCs in dwarf galaxies are slightly less
alpha-enhanced (by about 0.04 dex on average) than those in larger galaxies.
One GC in M33 (HM33-B) resembles the most metal-rich GCs in the Fornax dSph
(Fornax 4) and NGC 6822 (SC7) by having alpha-element abundances closer to
scaled-solar values, possibly hinting at an accretion origin. We find that the
alpha-element abundances strongly correlate with those of Na, Sc, Ni, and Zn.
Several GCs with [Fe/H]<-1.5 are deficient in Mg compared to other
alpha-elements. We find no GCs with strongly enhanced r-process abundances as
reported for metal-poor stars in some ultra-faint dwarfs and the Magellanic
Clouds. The similarity of the abundance patterns for metal-poor GCs in
different environments points to similar early enrichment histories and only
allow for minor variations in the initial mass function.
