WASHINGTON PHOTOMETRY OF THE GLOBULAR CLUSTERS IN THE VIRGO GIANT ELLIPTICAL GALAXY M86

Abstract

We present a photometric study of the globular clusters (GCs) in the Virgo giant elliptical galaxy M86 based on Washington <TEX>$CT_1$</TEX> images. The colors of the GCs in M86 show a bimodal distribution with a blue peak at (<TEX>$C-T_1$</TEX>) = 1.30 and a red peak at (<TEX>$C-T_1$</TEX>) = 1.72. The spatial distribution of the red GCs is elongated similar to that of the stellar halo, while that of the blue GCs is roughly circular. The radial number density profile of the blue GCs is more extended than that of the red GCs. The radial number density profile of the red GCs is consistent with the surface brightness profile of the M86 stellar halo. The GC system has a negative radial color gradient, which is mainly due to the number ratio of the blue GCs to the red GCs increasing as galactocentric radius increases. The bright blue GCs in the outer region of M86 show a blue tilt: the brighter they are, the redder their mean colors get. These results are discussed in comparison with other Virgo giant elliptical galaxies.