Washington Photometry of the Globular Clusters in the Virgo Giant Elliptical Galaxy M86

TL;DR

This study analyzes the globular cluster system of M86, revealing bimodal color distribution, spatial and radial density differences, and a color gradient, providing insights into galaxy formation and evolution.

Contribution

It presents detailed photometric analysis of GCs in M86 using Washington CT1 images, highlighting their distribution, color properties, and gradients, which are compared with other Virgo ellipticals.

Findings

Bimodal color distribution of GCs with peaks at (C -T1) = 1.30 and 1.72

Red GCs are spatially elongated, blue GCs are more circular

Blue GCs have a more extended radial density profile

Abstract

We present a photometric study of the globular clusters (GCs) in the Virgo giant elliptical galaxy M86 based on Washington CT1 images. The colors of the GCs in M86 show a bimodal distribution with a blue peak at (C -T1) = 1.30 and a red peak at (C -T1) = 1.72. The spatial distribution of the red GCs is elongated similarly 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 increase. 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.