2018ApJ...863..145C

We present a strong lensing analysis of four massive galaxy clusters imaged with the Hubble Space Telescope in the Reionization Lensing Cluster Survey. We use a light-traces-mass technique to uncover sets of multiple images and constrain the mass distribution of the clusters. These mass models are the first published for Abell S295 and MACS J0159.8-0849 and are improvements over previous models for Abell 697 and MACS J0025.4-1222. Our analysis for MACS J0025.4-1222 and Abell S295 shows a bimodal mass distribution supporting the merger scenarios proposed for these clusters. The updated model for MACS J0025.4-1222 suggests a substantially smaller critical area than previously estimated. For MACS J0159.8-0849 and Abell 697, we find a single peak and relatively regular morphology revealing fairly relaxed clusters. Despite being less prominent lenses, three of these clusters seem to have lensing strengths, i.e., cumulative area above certain magnification, similar to those of the Hubble Frontier Fields clusters (e.g., A(µ > 5) ∼ 1-3 arcmin², A(µ > 10) ∼ 0.5-1.5 arcmin²), which in part can be attributed to their merging configurations. We make our lens models publicly available through the Mikulski Archive for Space Telescopes. Finally, using Gemini-N/GMOS spectroscopic observations, we detect a single emission line from a high-redshift J₁₂₅ ≃ 25.7 galaxy candidate lensed by Abell 697. While we cannot rule out a lower-redshift solution, we interpret the line as Lyα at z = 5.800 ± 0.001, in agreement with its photometric redshift and dropout nature. Within this scenario, we measure a Lyα rest-frame equivalent width of 52 ± 22 Å and an observed Gaussian width of 117 ± 15 km s^–1.