The XXL Survey

Abstract

Context. The luminosity function (LF) is a powerful statistical tool used to describe galaxies and learn about their evolution. In particular, the LFs of galaxies inside clusters allow us to better understand how galaxies evolve in these dense environments. Knowledge of the LFs of galaxies in clusters is also crucial for clusters studies in the optical and near-infrared (NIR) as they encode, along with their density profiles, most of their observational properties. However, no consensus has been reached yet about the evolution of the cluster galaxy LF with halo mass and redshift. Aims. The main goal of this study is to investigate the LF of a sample of 142 X-ray selected clusters, with spectroscopic redshift confirmation and a well defined selection function, spanning a wide redshift and mass range, and to test the LF dependence on cluster global properties, in a homogeneous and unbiased way. Methods. Our study is based on the Canada–France–Hawaii Telescope Legacy Survey (CFHTLS) photometric galaxy catalogue, associated with photometric redshifts. We constructed LFs inside a scaled radius using a selection in photometric redshift around the cluster spectroscopic redshift in order to reduce projection effects. The width of the photometric redshift selection was carefully determined to avoid biasing the LF and depended on both the cluster redshift and the galaxy magnitudes. The purity was then enhanced by applying a precise background subtraction. We constructed composite luminosity functions (CLFs) by stacking the individual LFs and studied their evolution with redshift and richness, analysing separately the brightest cluster galaxy (BCG) and non-BCG members. We fitted the dependences of the CLFs and BCG distributions parameters with redshift and richness conjointly in order to distinguish between these two effects. Results. We find that the usual photometric redshift selection methods can bias the LF estimate if the redshift and magnitude dependence of the photometric redshift quality is not taken into account. Our main findings concerning the evolution of the galaxy luminosity distribution with redshift and richness are that, in the inner region of clusters and in the redshift-mass range we probe (about 0 < z < 1 and 1013 M⊙ < M500 < 5 × 1014 M⊙), the bright part of the LF (BCG excluded) does not depend much on mass or redshift except for its amplitude, whereas the BCG luminosity increases both with redshift and richness.

Dark Energy Survey Year 1 Results: Detection of Intracluster Light at Redshift ∼ 0.25

“…As discussed in Section 5.1, we assume a single Schechter luminosity function to estimate the light residual from faint unmasked cluster galaxies. As with the parameters of the Schechter function, given recent measurement uncertainties of the cluster galaxy luminosity function (e.g., Lan et al 2016;Ricci et al 2018), we find that varying the faint-end slope parameter by ±0.2 or the characteristic magnitude parameter by ±0.5 mag changes the estimated fraction of residual light by ∼ 1%.…”

SPIDERS: overview of the X-ray galaxy cluster follow-up and the final spectroscopic data release

“…Jones & Forman 1999). They appear as diffuse extended sources (Abell 1958;Bahcall & Cen 1993;Böhringer et al 2004;Oguri et al 2018;Ridl et al 2017;Ricci et al 2018;Wen & Han 2018;Andreon et al 2019;Gozaliasl et al 2019), with galaxy overdensities extending out to over 10 Mpc (Trevisan et al 2017). Galaxies within halos may have their properties affected by encounters with the hot gas (e.g., Popesso et al 2015;Lotz et al 2019;Owers et al 2019).…”

AMICO galaxy clusters in KiDS-DR3: Evolution of the luminosity function betweenz= 0.1 andz= 0.8

“…Evolutive correction is not applied since we want to investigate this. In this work, the stacking of the LF is done as proposed by Garilli et al (1999), since the Colless (1989) method was shown in Ricci et al (2018) to assign more weight to the poor clusters. Following these prescriptions, the stacked LF is built by summing the cluster galaxies in absolute magnitude bins and scaling it by the richness of their parent clusters as follows:…”