The buildup of the intracluster light of Abell 85 as seen by Subaru's Hyper Suprime-Cam

TL;DR

This paper demonstrates that careful data processing of Subaru Hyper Suprime-Cam archival images can reveal the diffuse intracluster light in Abell 85, measuring its properties and suggesting its buildup through satellite stripping.

Contribution

It provides a method to detect and analyze intracluster light in deep imaging data, overcoming previous over-subtraction issues and measuring its extent, color, and fraction in Abell 85.

Findings

Intracluster light becomes dominant beyond 75 kpc.

Color profiles indicate buildup from stripping massive satellites.

Fraction of intracluster light ranges from 8% to 30%.

Abstract

The study of low surface brightness light in large, deep imaging surveys is still uncharted territory as automated data reduction pipelines over-subtract or eliminate this light. Using archival data of the Abell 85 cluster of galaxies taken with Hyper Suprime-Cam on the Subaru Telescope, we show that using careful data processing can unveil the diffuse light within the cluster, the intracluster light. We reach surface brightness limits of $\mu_{g}^{limit}$(3$\sigma$, 10"x10") = 30.9 mag/arcsec$^2$, and $\mu_{i}^{limit}$(3$\sigma$, 10"x10") = 29.7 mag/arcsec$^2$. We measured the radial surface brightness profiles of the brightest cluster galaxy out to the intracluster light (radius $\sim215$ kpc), for the g and i bands. We found that both the surface brightness and the color profiles become shallower beyond $\sim75$ kpc suggesting that a distinct component, the intracluster light, starts to dominate at that radius. The color of the profile at $\sim100$ kpc suggests that the buildup of the intracluster light of Abell 85 occurs by the stripping of massive ($\sim10^{10}M_{\odot}$) satellites. The measured fraction of this light ranges from 8% to 30% in g, depending on the definition of intracluster light chosen.