Galaxy clusters are the ultimate manifestation of hierarchical structure formation, and they continue to grow and accrete matter at the present time. A plethora of unexplored physics is believed to be operating near and beyond the virial radii of galaxy clusters, and these processes are fundamentally different from the physics in the cores of clusters that has been the focus of X-ray cluster science over the past several decades. The outer regions of galaxy clusters and groups, at the interface with the Warm-Hot Intergalacitc Medium, bear witness to the complex phenomena of large-scale structure growth as it happens. The rich thermal, kinematic and chemical contents of cluster outskirts are the Rosetta stone for understanding the growth of galaxy clusters and their connections to the Cosmic Web. Only a synergetic combination of multi-bands observations (X-ray and mm bands to trace the distribution of the hot gas; radio to resolve non-thermal processes; optical to recover weak lensing signal induced from dark matter and the galaxy distribution) and modern hydrodynamical cosmological simulations can provide the ultimate census of the mass and energetics of the baryons in collapsed structures.

Programme

• Presentation of the state-of-art researches on the groups & clusters' peripheries, both from multi-band (from optical to radio, SZ, and X-ray) observations, and numerical simulations, and theoretical models
• Deep discussion on the present limitations affecting the analysis of these regions, and how we can overcome these problems with the present and next generation instruments from radio (LOFAR, SKA) to SZ (CMB-S4, Simmons Observatory), from optical (Euclid, LSST) to X-ray (eROSITA, XRISM, Athena)

Invited speakers

• Nabila Aghanim (Paris Sud University, Orasy, France)
• Veronica Biffi (LMU University, Munich, Germany)
• Esra Bulbul (MPE, Garching, Germany)
• Nicholas Battaglia (Cornell University, US)
• Thomas Reiprich (Bonn University, Germany)
• Franco Vazza (Bologna University, Italy)
• Reinout J. van Weeren (Leiden University, The Netherlands)

Scientific organisers

• S. Ettori (INAF-OAS, Bologna, Italy)
• A. Simionescu (SRON, Utrecht, The Netherlands)
• D. Nagai (Yale University, USA)

Contact

stefano.ettori@inaf.it, a.simionescu@sron.nl, daisuke.nagai @ yale.edu