Reconstructing orbits of galaxies in extreme regions (ROGER)

Abstract

Context. Clusters of galaxies have proven to be efficient systems in modifying various properties of galaxies, such as star formation or morphology. However, projection effects impose serious challenges in determining how, when, and to what extent galaxies are affected by the cluster environment.Aims. Using innovative techniques to classify galaxies based on their history within the cluster, we aim to determine how galaxies of different classes are affected by the cluster environment.Methods. We applied the ROGER code to select trajectories of galaxies in the phase space for 35 galaxy clusters from the OmegaWINGS survey. A new algorithm was applied to minimize contamination effects.Results. We found that both morphological transformation and the quenching of star formation begin shortly after galaxies enter the cluster. Even though over the last 2 − 3 Gyr, galaxies entering clusters have undergone significant transformations in both their star formation and morphology these transformation processes are not complete, that is, they are not completely quenched and are not early type yet. Backsplash galaxies and recent infallers show a higher fraction of jellyfish galaxies compared to older cluster members, suggesting that the timescale of this phenomenon is typically less than 3 Gyr.