The old globular cluster system of NGC 4365: new VLT/FORS2 spectra
  We present new spectroscopic observations of a sample of globular clusters
(GCs) in the Virgo Cluster elliptical NGC4365. The great majority of the
objects analysed here, overlap on purpose with objects presented in two
previous studies that came to contradictory conclusions. We measure Lick
indices for the GCs and infer ages, abundances and alpha-enhancement values by
comparing to population synthesis models. Our results do not support the
existence of numerous intermediate-age GCs in this galaxy as suggested by some
of the past studies. Instead, we find ages, consistent with the range ~8-14
Gyrs (model dependent and with large uncertainties). We also find that the
newly observed GCs have [Fe/H]\sim-1.3 to 0.3 dex and the majority are
consistent with [alpha/Fe]\sim0.3 dex, independent of metallicity. By comparing
the metal sensitive index [MgFe] with optical colours, we find that our data is
consistent with 14Gyr models. However for optical/near-infrared colours we find
that the same models would have to be redder by ~0.2 mag in order to be
consistent with our data. This offset is not found to be consistent with an age
effect as it is even larger for younger models.
