Sunyaev Zel’dovich study of filamentary structuresbetween galaxy clusters

The Sunyaev Zel’dovich (SZ) effect can be used to map the inter-cluster region between galaxy clusters especially in particular cases of superclusters of galaxies and pairs of galaxy clusters in the premerging phase. Such direct detection would be fundamental for the study of filamentary structures between galaxy clusters and shed light on the open problem of the missing baryons in our Universe as well as on the hierarchical structure formation scenario. We take as example the Abell401-Abell399 cluster pair, which has been observed at low-angular resolution by the Planck satellite and is a well-studied structure that exhibits double radio-halos, an ex-cess of X-ray emission in the bridge connecting the clusters, and even the presence of a shock front indicating the cluster pair’s pre-merging status. The Planck satellite was able to model the emission from the bridge between the clusters pair despite the poor angular resolution ('5’) of its SZ maps, and proposed that at least part of the signal in the inter-cluster region (y'5 10^(-6) over a total of y'15 10^(-6)) is due to a pre-existing filamentary structure. A bolometric camera observing at '3mm, coupled to a 50-to-100m class radio telescope would be the ideal instrument in terms of angular resolution and sensitivity to disentangle different scenarios.