RELICS: Strong Lens Models for Five Galaxy Clusters from the Reionization Lensing Cluster Survey

Abstract

Strong gravitational lensing by galaxy clusters magnifies background galaxies, enhancing our ability to discover statistically significant samples of galaxies at z 6 > , in order to constrain the high-redshift galaxy luminosity functions. Here, we present the first five lens models out of the Reionization Lensing Cluster Survey (RELICS) Hubble Treasury Program, based on new HST WFC3/IR and ACS imaging of the clusters RXCJ0142.9+4438, Abell2537, Abell2163, RXCJ2211.7-0349, and ACT-CLJ0102-49151. The derived lensing magnification is essential for estimating the intrinsic properties of high-redshift galaxy candidates, and properly accounting for the survey volume. We report on new spectroscopic redshifts of multiply imaged lensed galaxies behind these clusters, which are used as constraints, and detail our strategy to reduce systematic uncertainties due to lack of spectroscopic information. In addition, we quantify the uncertainty on the lensing magnification due to statistical and systematic errors related to the lens modeling process, and find that in all but one cluster, the magnification is constrained to better than 20% in at least 80% of the field of view, including statistical and systematic uncertainties. The five clusters presented in this paper span the range of masses and redshifts of the clusters in the RELICS program. We find that they exhibit similar strong lensing efficiencies to the clusters targeted by the Hubble Frontier Fields within the WFC3/IR field of view. Outputs of the lens models are made available to the community through the Mikulski Archive for Space Telescopes.

RELICS: spectroscopy of gravitationally lensed z ≃ 2 reionization-era analogues and implications for C iii] detections at z > 6

“…The magnification provided by the cluster is calculated from lens models prepared by the RELICS team and available to the public. 1 Further details on the lens modeling procedure have been presented in recent RELICS papers (Cerny et al 2018;Paterno-Mahler et al 2018;Cibirka et al 2018;Acebron et al 2018). In calculating the magnification and the absolute magnitude, we assume the confirmed spectroscopic redshift presented in §3.…”

RELICS: A Strong Lens Model for SPT-CLJ0615–5746, a z = 0.972 Cluster

“…The strong lensing analysis by Cerny et al (2018) finds that M 500 kpc 11.0 0.7 < = ( ) 10 14 M ☉ , also in good agreement. Other strong lensing clusters with complete models in this high-redshift regime include RCS 0224-0002 (z=0.773; Gladders et al 2002;Smit et al 2017) with M 1.9 0.1 10 200,SL 14 = ´M ☉ (Rzepecki et al 2007), and RCS2 J232727.6-020437 (z=0.7;Gilbank et al 2011;Menanteau et al 2013;Hoag et al 2015) (Sharon et al 2015;Schrabback et al 2018b).…”

“…The cluster selection process is described in detail in Cerny et al (2018) andD. Coe et al (2018, in preparation), and strong lensing analyses for other RELICS clusters were published in Cerny et al (2018), Acebron et al (2018), andCibirka et al (2018). SPT0615 was observed for two orbits with the Wide Field Camera 3 (WFC3) in F105W, F125W, F140W, and F160W and for one orbit with the Advanced Camera for Survey (ACS) in F435W.…”

MIFAL: fully automated Multiple-Image Finder ALgorithm for strong-lens modelling – proof of concept

“…Despite the various methods available for SL analyses or mass modelling, only several dozen clusters have been analysed to date with regards to their SL features (albeit with rapidly increasing numbers), with the vast majority only in the last decade or so (e.g. Smith et al 2005;Richard et al 2010;Zitrin et al 2015;Kawamata et al 2016;Cerny et al 2018;Acebron et al 2018). One of the main reasons, apart from the finite amount of high-resolution data particularly from space, is that nearly all methods are often time-consuming and the analysis has to be performed on a particular basis with significant intervention and fine-tuning by the user.…”