# Quantifying the suppression of the (un)-obscured star formation in galaxy cluster cores at 0.2$\lesssim$$z$$\lesssim$0.9

## TL;DR

This study quantifies how star formation is suppressed in the cores of galaxy clusters between redshifts 0.2 and 0.9, revealing that both the fraction of star-forming galaxies and their star formation rates are lower than in the field, indicating long-term quenching processes.

## Contribution

It provides the first comprehensive analysis of star formation suppression in cluster cores over a broad redshift range using multi-wavelength data and publicly released catalogs.

## Key findings

- Star formation activity is roughly halved in cluster cores compared to the field.
- Star formation rates and specific SFRs are about 0.3 dex lower in clusters across the studied redshift range.
- Long time-scale quenching processes dominate in suppressing star formation in cluster cores.

## Abstract

We quantify the star formation (SF) in the inner cores ($\mathcal{R}$/$R_{200}$$\leq$0.3) of 24 massive galaxy clusters at 0.2$\lesssim$$z$$\lesssim$0.9 observed by the $Herschel$ Lensing Survey and the Cluster Lensing and Supernova survey with $Hubble$. These programmes, covering the rest-frame ultraviolet to far-infrared regimes, allow us to accurately characterize stellar mass-limited ($\mathcal{M}_{*}$$>$$10^{10}$ $M_{\odot}$) samples of star-forming cluster members (not)-detected in the mid- and/or far-infrared. We release the catalogues with the photometry, photometric redshifts, and physical properties of these samples. We also quantify the SF displayed by comparable field samples from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey. We find that in intermediate-$z$ cluster cores, the SF activity is suppressed with respect the field in terms of both the fraction ($\mathcal{F}$) of star-forming galaxies (SFG) and the rate at which they form stars ($\mathcal{SFR}$ and $s\mathcal{SFR} = \mathcal{SFR}/\mathcal{M}_{*}$). On average, the $\mathcal{F}$ of SFGs is a factor $\sim$$2$ smaller in cluster cores than in the field. Furthermore, SFGs present average $\mathcal{SFR}$ and $s\mathcal{SFR}$ typically $\sim$0.3 dex smaller in the clusters than in the field along the whole redshift range probed. Our results favour long time-scale quenching physical processes as the main driver of SF suppression in the inner cores of clusters since $z$$\sim$0.9, with shorter time-scale processes being very likely responsible for a fraction of the missing SFG population.