When the Well Runs Dry: Modeling Environmental Quenching of High-mass Satellites in Massive Clusters at \boldmath$z \gtrsim 1$

TL;DR

This study models environmental quenching of high-mass satellite galaxies in massive clusters at redshift around 1, identifying two potential quenching pathways and concluding that starvation is the dominant mechanism based on observational data.

Contribution

The paper introduces an MCMC framework to distinguish between starvation and core quenching pathways in high-redshift clusters, providing new insights into satellite galaxy quenching mechanisms.

Findings

Two quenching pathways identified: starvation and core quenching.

Starvation pathway aligns with observed transition galaxy properties at z~1.

Core quenching involves rapid quenching in the cluster core with high velocities.

Abstract

We explore models of massive ($\gt 10^{10}~{\rm M}_{\odot}$) satellite quenching in massive clusters at $z\gtrsim1$ using an MCMC framework, focusing on two primary parameters: $R_{\rm quench}$ (the host-centric radius at which quenching begins) and $\tau_{\rm quench}$ (the timescale upon which a satellite quenches after crossing $R_{\rm quench}$). Our MCMC analysis shows two local maxima in the 1D posterior probability distribution of $R_{\rm quench}$ at approximately $0.25$ and $1.0~R_{\rm{200}}$. Analyzing four distinct solutions in the $\tau_{\rm quench}$-$R_{\rm quench}$ 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 \textquote{starvation} and \textquote{core quenching} scenarios. The starvation pathway is characterized by quenching timescales that are roughly consistent with the total cold gas (H$_{2}$+H{\scriptsize I}) depletion timescale at intermediate $z$, while core quenching is characterized by satellites with relatively high line-of-sight velocities that quench on short timescales ($\sim 0.25$ Gyr) after reaching the inner region of the cluster ($\lt 0.30~R_{\rm{200}}$). 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 \textquote{starvation} pathway is consistent with the projected phase-space distribution and relative abundance of transition galaxies at $z \sim 1$. However, we acknowledge that ram pressure might contribute as a secondary quenching mechanism.