Is diffuse intracluster light a good tracer of the galaxy cluster matter distribution?

Abstract

We explore the relation between diffuse intracluster light (central galaxy included) and the galaxy cluster (baryonic and dark) matter distribution using a sample of 528 clusters at 0.2 ≤ z ≤ 0.35 found in the Dark Energy Survey (DES) Year 1 data. The surface brightness of the diffuse light shows an increasing dependence on cluster total mass at larger radius, and appears to be self-similar with a universal radial dependence after scaling by cluster radius. We also compare the diffuse light radial profiles to the cluster (baryonic and dark) matter distribution measured through weak lensing and find them to be comparable. The IllustrisTNG galaxy formation simulation, TNG300, offers further insight into the connection between diffuse stellar mass and cluster matter distributions – the simulation radial profile of the diffuse stellar component does not have a similar slope with the total cluster matter content, although that of the cluster satellite galaxies does. Regardless of the radial trends, the amount of diffuse stellar mass has a low-scatter scaling relation with cluster’s total mass in the simulation, out-performing the total stellar mass of cluster satellite galaxies. We conclude that there is no consistent evidence yet on whether or not diffuse light is a faithful radial tracer of the cluster matter distribution. Nevertheless, both observational and simulation results reveal that diffuse light is an excellent indicator of the cluster’s total mass.

Quantified diffuse light in compact groups of galaxies

“…They also found the similarity of these distributions. The results of Montes & Trujillo (2019) and Sampaio-Santos et al (2020) are confirmed by recent N-body simulations (Alonso Asensio et al 2020).…”

On the Origin and Evolution of the Intra-Cluster Light: A Brief Review of the Most Recent Developments

“…We have seen above that the ICL is dynamically bound to the host cluster, and we know from several studies that more massive haloes host the most massive BCGs ( [4,89,121,132,133] and others), which means that both growths of ICL and BCG are linked to the host cluster. It is, then, reasonable to expect BCG and ICL to co-evolve at some time during their assembly.…”

“…This year (2021) has been, so far, very fruitful on this topic. Sampaio-Santos et al [89] explored the connection between BCG + ICL and the total cluster mass distributions by using a sample of more than 500 clusters between redshift 0.2 < z < 0.35 from the Dark Energy Survey. Similarly to Zhang et al [10], who also used a sample (but smaller) from the same survey, found that the surface brightness of the BCG + ICL has a universal radial dependence after scaling it by cluster radius.…”

“…Nevertheless, they concluded that there is not sufficient evidence to entitle the diffuse light as a good tracer of the cluster matter distribution, but it is an excellent indicator of the total cluster mass. It must be noted, however, that Montes; Trujillo [84] used strong lensing maps, which are more robust than the weak lensing maps used by Sampaio-Santos et al [89]. Kluge et al [33] studied the BCG and ICL alignments with the host cluster and found that the ICL is better aligned than the BCG in terms of position angle, ellipticity and centering.…”

“…Among the most important properties of the ICL, its radial distribution is surely one of them and it can shed some light on two delicate topics: The dynamical state of clusters (e.g., [50,81,82]) and the dark matter (hereafter DM) distribution. Recently, there have been many attempts (e.g., [10,[83][84][85][86][87][88][89][90][91][92]) to link the ICL with the DM in clusters. For instance, Montes; Trujillo [84], with a sample of six clusters from the Hubble Frontier Fileds [93], investigated the ICL and DM distributions by means of the modified Hausdorff distance, a method that connects the two distributions and quantifies how far the two components are from each other.…”