MULTICOLOR CCD PHOTOMETRY OF GLOBULAR-CLUSTERS IN 2 VIRGO ELLIPTIC GALAXIES

We present new CCD photometry in the BVI system for a sample of globular clusters in NGC 4472, and in BV for NGC 4649. Both of these represent "normal" globular cluster systems in giant elliptical galaxies. Just as in the Virgo central giant M87, we find that the clusters in both these galaxies show a large dispersion in color (corresponding to sigma([Fe/H]) congruent-to 0.6) at any radius from the center, and that they are distinctly bluer (DELTA([Fe/H]) congruent-to 0.5) than the integrated halo light. However, quite unlike M87, we find a clear radial gradient in the mean cluster colors in both NGC 4472 and 4649, suggesting that the role of dissipational collapse was more important in their formation than it was in M87.