Astronomy seminar

Dissecting a miniature universe: A multi-wavelength view of galaxy quenching in the Shapley supercluster

Toni Kalevi Tuominen

Multiple-cluster systems, i.e. superclusters, contain large numbers of galaxies assembled in clusters inter-connected by multi-scale filamentary networks. As such, superclusters are a smaller version of the cosmic web and can hence be considered as miniature universes. In addition to the galaxies, superclusters also contain gas, hot in the clusters and warmer in the filaments. Therefore, they are ideal laboratories to study the interplay between the galaxies and the gas. In this context, the Shapley supercluster (SSC) stands out since since it hosts the highest number of galaxies in the local universe with clusters interconnected by filaments. In this presentation I will describe the supercluster and show its filamentary network as detected with the T-REx filament finding method. In addition, comparing the star formation rates of a large sample of photometric galaxies with the gas pressure detected via the thermal Sunyaev-Zel’dovich (tSZ) effect, I will characterise the quenching of star formation towards the core of the supercluster. Indeed, our results suggest the zone of influence of the SSC, in which galaxies are pre-processed and quenched, is well defined by the tSZ signal that combines the density and temperature of the environments.

Seminar takes place in Tartu Observatory, Tõravere and is streamed over Zoom.

All 2023/24 seminars.