The Grism lens-amplified survey from space (GLASS). VIII. The influence of the cluster properties on Halpha emitter galaxies at 0.3<z<0.7

TL;DR

This study uses space-based grism data to analyze how cluster environments influence star-forming galaxies at intermediate redshifts, revealing local effects are more impactful than global cluster properties.

Contribution

It provides the first detailed analysis of Hα emitter spatial distribution and offsets in clusters at 0.3<z<0.7, highlighting the importance of local environmental effects.

Findings

Hα emitters are found up to 0.5 virial radii in clusters.

Offsets in Hα emission correlate with galaxy velocity and ram-pressure signatures.

Local density influences Hα morphology more than cluster-centric radius.

Abstract

Exploiting the data of the Grism Lens-Amplified Survey from Space (GLASS), we characterize the spatial distribution of star formation in 76 high star forming galaxies in 10 clusters at 0.3< z <0.7. All these galaxies are likely restricted to first infall. In a companion paper we contrast the properties of field and cluster galaxies, whereas here we correlate the properties of H{\alpha} emitters to a number of tracers of the cluster environment to investigate its role in driving galaxy transformations. H{\alpha} emitters are found in the clusters out to 0.5 virial radii, the maximum radius covered by GLASS. The peak of the H{\alpha} emission is offset with respect to the peak of the UV-continuum. We decompose this offsets into a radial and tangential component. The radial compo- nent points away from the cluster center in 60% of the cases, with 95% confidence. The decompositions agree with cosmological simulations, i.e. the H{\alpha} emission offset correlates with galaxy velocity and ram-pressure stripping signatures. Trends between H{\alpha} emitter properties and surface mass density distributions and X-ray emissions emerge only for unrelaxed clusters. The lack of strong correlations with the global environment does not allow us to identify a unique environmental effect originating from the cluster center. In contrast, correla- tions between H{\alpha} morphology and local number density emerge. We conclude that local effects, uncorrelated to the cluster-centric radius, play a more important role in shaping galaxy properties.