Measurement of the intracluster light at z∼1

Abstract

A significant fraction of the total photospheric light in nearby galaxy clusters is thought to be contained within the diffuse intracluster light (ICL), which extends hundreds of kpc from cluster cores. The study of the ICL can reveal details of the evolutionary histories and processes occurring within galaxy clusters; however, since it has a very low surface brightness, it is often difficult to detect. We present here the first measurements of the ICL as a fraction of the total cluster light at z ∼ 1 using deep J‐band (1.2 μm) imaging from a high‐acuity wide‐field K‐band imager on the Very Large Telescope. We investigate the ICL in six X‐ray selected galaxy clusters at 0.8 ≤ z ≤ 1.2 and find that the ICL below isophotes μJ = 22 mag arcsec−2 constitutes 1–4 per cent of the total cluster light within a radius R500. This is broadly consistent with simulations of the ICL at a similar redshift and when compared to nearby observations suggests that the fraction of the total cluster light that is in the ICL has increased by a factor of 2–4 since z ∼ 1. We also find the fraction of the total cluster light contained within the brightest cluster galaxy (BCG) to be 2.0–6.3 per cent at these redshifts, which in five out of six cases is larger than the fraction of the ICL component, in contrast to the results from nearby clusters. This suggests that the evolution in cluster cores involves substantial stripping activity at late times, in addition to the early build‐up of the BCG stellar mass through merging. The presence of significant amount of stellar light at large radii from these BCGs may help towards solving the recent disagreement between the semi‐analytic model predictions of BCG mass growth and the observed large masses and scale sizes reported for BCGs at high redshift.

Diffuse light in the young cluster of galaxies CL J1449+0856 atz= 2.07

“…Diffuse light becomes an important aspect in clusters of galaxies as shown by recent studies (Gregg & West 1998;Mihos et al 2005;Zibetti et al 2005;González et al 2007;Krick & Bernstein 2007;Rudick et al 2010;Burke et al 2012). It finds its origin at least partly in matter ejections from galaxies during galaxy-galaxy or galaxy-cluster potential interactions (see e.g.…”

“…Guennou et al (2012) used deep HST ACS data to detect diffuse light for ten clusters between z = 0.4 and 0.8 and did not detect any significant variation in the cluster diffuse light content with redshift. By applying a somewhat less sophisticated method, Burke et al (2012) extended this search to a sample of six clusters at z ∼ 1 based on VLT/HAWK-I data, and found that intracluster light (hereafter ICL) only composed (1−4)% of the total cluster light.…”

Intra-cluster Globular Clusters in a Simulated Galaxy Cluster

“…Stars that have been removed from their parent galaxy can be observed in galaxy clusters as a diffuse light, called intracluster light. However, its observational detection is very difficult due to the extremely low surface brightness of the intra-cluster light, which contains ∼ 10%−30% of the total optical luminosity of the galaxy clusters (Gregg and West 1998;Mihos et al 2005;Krick and Bernstein 2007;Burke et al 2012;Mihos 2015).…”

Detection of the Stellar Intracluster Medium in Perseus (Abell 426)

“…Assessing the true fraction of the ICL component relative to the individual galaxies is a continuing and difficult issue since it requires careful separation of the ICL profile from the giant galaxies in the cluster, but is almost certainly in the range 10-50% for rich clusters and even groups (Gonzalez et al 2005; Da Rocha & Mendes de Oliveira 2005; Seigar et al 2007;Rudick et al 2011;Giallongo et al 2014;Jiménez-Teja & Dupke 2016). The growth of the ICL is an ongoing process with much of it happening since redshift z ∼ 1 (Burke et al 2012(Burke et al , 2015Adami et al 2013;Presotto et al 2014), so the total luminosity in the ICL and its degree of substructure (clumps and tidal streams) are indicative of the dynamical evolutionary state of the cluster.…”