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 SED fitting results from JWST/NIRCam photometry, the fraction of quenched galaxies in this cluster was measured in two bins of stellar mass: $9<\log (M_{\ast }/{\mathrm{M}}_{\odot })<10$ and $10\le \log (M_{\ast }/{\mathrm{M}}_{\odot })<12$. 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 $z\sim 1$, and that dwarf galaxies are more affected by those processes than massive galaxies.