When the well runs dry: modelling environmental quenching of high-mass satellites in massive clusters at z ≳ 1

We explore models of massive (>10¹⁰ M_⊙) satellite quenching in massive clusters at z ≳ 1 using an MCMC framework, focusing on two primary parameters: R_quench (the host-centric radius at which quenching begins) and τ_quench (the time-scale upon which a satellite quenches after crossing R_quench). Our MCMC analysis shows two local maxima in the 1D posterior probability distribution of R_quench at approximately 0.25 and 1.0 R₂₀₀. Analysing four distinct solutions in the τ_quench–R_quench parameter space, nearly all of which yield quiescent fractions consistent with observational data from the GOGREEN survey, we investigate whether these solutions represent distinct quenching pathways and find that they can be separated between ‘starvation’ and ‘core quenching’ scenarios. The starvation pathway is characterized by quenching time-scales that are roughly consistent with the total cold gas (H₂ + H I) depletion time-scale at intermediate z, while core quenching is characterized by satellites with relatively high line-of-sight velocities that quench on short time-scales (∼0.25 Gyr) after reaching the inner region of the cluster (<0.30 R₂₀₀). Lastly, we break the degeneracy between these solutions by comparing the observed properties of transition galaxies from the GOGREEN survey. We conclude that only the ‘starvation’ pathway is consistent with the projected phase-space distribution and relative abundance of transition galaxies at z ∼ 1. However, we acknowledge that ram pressure might contribute as a secondary quenching mechanism.