STRUCTURAL PARAMETERS OF THE MESSIER 87 GLOBULAR CLUSTERS**Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program 10543.

We derive structural parameters for ∼2000 globular clusters in the giant Virgo elliptical Messier 87 (M87) using extremely deep Hubble Space Telescope images in F606W (V) and F814W (I) taken with the ACS/WFC. The cluster scale sizes (half-light radii rh) and ellipticities are determined from point-spread-function -convolved King-model profile fitting. We find that the rh distribution closely resembles the inner Milky Way clusters, peaking at rh …