Optical Colors of Intracluster Light in the Virgo Cluster Core

TL;DR

This study uses deep optical imaging to analyze the intracluster light in the Virgo cluster core, revealing low-surface brightness features and their colors, which suggest a common origin with the cD galaxy M87's halo.

Contribution

It provides detailed B-band surface photometry of Virgo's intracluster light and compares colors of ICL features with M87's halo, indicating a shared formation process.

Findings

ICL features extend beyond M87's outer regions.

Colors of ICL features are similar to M87's halo (B-V ~ 0.8).

Blueing trend in M87's color profile with radius.

Abstract

We continue our deep optical imaging survey of the Virgo cluster using the CWRU Burrell Schmidt telescope by presenting B-band surface photometry of the core of the Virgo cluster in order to study the cluster's intracluster light (ICL). We find ICL features down to mu_b ~ 29 mag sq. arcsec, confirming the results of Mihos et al. (2005), who saw a vast web of low-surface brightness streams, arcs, plumes, and diffuse light in the Virgo cluster core using V-band imaging. By combining these two data sets, we are able to measure the optical colors of many of the cluster's low-surface brightness features. While much of our imaging area is contaminated by galactic cirrus, the cluster core near the cD galaxy, M87, is unobscured. We trace the color profile of M87 out to over 2000 arcsec, and find a blueing trend with radius, continuing out to the largest radii. Moreover, we have measured the colors of several ICL features which extend beyond M87's outermost reaches and find that they have similar colors to the M87's halo itself, B-V ~ 0.8. The common colors of these features suggests that the extended outer envelopes of cD galaxies, such as M87, may be formed from similar streams, created by tidal interactions within the cluster, that have since dissolved into a smooth background in the cluster potential.