The innermost globular clusters of M87
  We present a comprehensive multiwavelength photometric analysis of the
innermost (3x3 square kpc) 110 globular clusters (GCs) of M87. Their spectral
energy distributions (SEDs) were built taking advantage of new ground-based
high resolution near-IR imaging aided by adaptive optics at the Very Large
Telescope (VLT) combined with Hubble Space Telescope (HST) ultraviolet--optical
archival data. These GC SEDs are among the best photometrically sampled
extragalactic GC SEDs. To compare with our SEDs we constructed equally sampled
SEDs of Milky Way GCs. Using both these Milky Way cluster templates and
different stellar population models, ages of >10 Gyr and metallicities of
[Fe/H] -0.6 dex are consistently inferred for the inner GCs of M87. In
addition, the metallicity of these GCs is low (Dif([Fe/H]) 0.8 dex) compared to
that of their host galaxy. These results agree with the idea that the GC
formation in M87 ceased earlier than that of the bulk of the stars of the
central part of the galaxy. The ages of the inner GCs of M87 support the idea
that these central parts of the galaxy formed first. Our data do not support
evidence of recent wet merging.
