The Distribution of Quenched Galaxies in the Massive z = 0.87 Galaxy Cluster El Gordo

Abstract El Gordo (ACT-CL J0102−4915) is a massive galaxy cluster with two major mass components at redshift z = 0.87. Using spectral energy distribution fitting results from JWST/NIRCam photometry, the fraction of quenched galaxies in this cluster was measured in two bins of stellar mass: 9 < log ( M * / M ⊙ ) < 10 and 10 ≤ log ( M * / M ⊙ ) < 12 . While there is no correlation between the quenched fraction and angular separation from the cluster’s overall center of mass, there is a correlation between the quenched fraction and angular separation from the center of the nearest of the two mass components for the less-massive galaxies. This suggests that environmental quenching processes are in place at z ∼ 1, and that dwarf galaxies are more affected by those processes than massive galaxies.