Event details

Date
June 21, 2027  – June 25, 2027
Location
Haus Sexten - Via Dolomiti 45, 39030, Sexten

Scientific Rationale

Galaxy groups, consisting of a few tens of galaxies bound within a common gravitational potential, dominate the halo mass function and host a large fraction of the baryons in the Universe. As such, they are key laboratories for understanding structure formation and the complex interplay between gravitational collapse and baryonic physics across cosmic time.
Understanding the mechanisms, such as AGN and stellar feedback, that regulate the exchange of mass, energy, and metals between galaxies, the circum-galactic medium (CGM), and the intra-group medium (IGrM) remains a cornerstone of modern galaxy formation models. While current theoretical frameworks successfully reproduce several global observables in massive clusters, they show significant discrepancies in their predictions for low-mass halos. These include the total baryon content, the thermodynamic and chemical properties of the gas, and the balance between gas removal and star formation regulation. In low-mass systems, where the feedback energy can be comparable to the halo binding energy, different implementations lead to markedly different outcomes, ranging from gas-poor halos to overly X-ray luminous systems. In addition, growing evidence points to the role of assembly history and large-scale environment (assembly bias), with galaxy group properties depending not only on halo mass but also on their location within the cosmic web (e.g., filaments, nodes, voids).
In recent years, major observational advances have begun to transform this picture. Multiwavelength observations provide a more complete view of galaxy groups, simultaneously probing the hot intra-group medium, the multiphase CGM, and the galaxy population itself. These data reveal a complex interplay between gas cooling, star formation, AGN activity, and non-thermal processes such as relativistic plasma and magnetic fields. In particular, at high redshift, group and cluster environments appear highly dynamic, shaped by ongoing accretion, mergers, and feedback processes that govern both the thermodynamic state of the gas and galaxy evolution. They therefore provide a unique window into the early phases of structure formation and the onset of baryon cycling in low-mass halos.

The goal of the conference is to provide an updated and comprehensive view of galaxy groups, focusing on the baryon cycle across scales, from the central galaxy to the CGM and the intra-group medium, and to identify the key open questions for the next decade.
The meeting will be structured around two main themes:
– Observational advances in galaxy groups and the baryon cycle:
• galaxy populations, star formation, and environmental effects across cosmic time, including dependencies on large-scale structure and assembly bias;
• thermodynamic and chemical properties of the intra-group medium from X-ray and SZ observations;
• multiphase structure of the CGM and its connection to galaxies from optical, UV, and submillimeter data;
• non-thermal components, including relativistic plasma, magnetic fields, and radio emission;
• statistical properties of large samples and stacking approaches in low surface brightness regimes;
• galaxy groups at high redshift: detection, characterization, and evolution of their baryonic components.

– Theoretical challenges and future perspectives:
• comparison between observations and state-of-the-art hydrodynamical simulations;
• modelling of AGN and stellar feedback across different mass scales;
• joint evolution of galaxies, CGM, and intra-group medium;
• role of assembly bias and large-scale environment in shaping galaxy group properties beyond halo mass;
• role of non-thermal processes and their implementation in simulations;
• formation and evolution of galaxy groups at high redshift in a cosmological context;
• key open questions and prospects for upcoming facilities

Organizers

SOC
Lovisari L., Gastaldello F., Ettori S., Croston J., Eckert D., Finoguenov A., Oppenheimer B., Pillepich A., Popesso P., Vulcani B.

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Payment details

Registration Fee
Senior: 350E PhD/students: 300E
Workshop code for bus and payment
GGL27