Conference organized by the "Department of Physics and Astronomy (DiFA) of the University of Bologna", and the "Osservatorio di Astrofisica e Scienza dello Spazio di Bologna (INAF-OAS)" in September 2024, to review the latest results on extragalactic studies of the baryon cycle, and to discuss their impact and consequences on our understanding of galaxy evolution from nearby galaxies up to the early Universe.

SCIENTIFIC RATIONALE

The 'baryon cycle'

Galaxies accrete gas from the intergalactic medium, thus building their gaseous reservoirs, which fuel the formation of stars and the growth of supermassive black holes. Feedback mechanisms then return part of this material into the circumgalactic environment, thus completing the so-called `baryon cycle'. Understanding this process (both at cloud- and galaxy-scales) and its dependence on cosmic times is one of the key question of modern astrophysics.

Over the last 10 years, the ALMA interferometer operating in the sub-mm/mm regime has opened a new window on the baryon cycle, allowing to study the cold inter-stellar medium (ISM) phase, the fuel of star-formation, to unprecedented levels of sensitivity and spatial resolution. The recent launch of JWST has a similarly transformational impact, as it pierces through dense dusty clouds and exposes the warm ISM phase in the near-IR and mid-IR regime and at virtually any cosmic time. These new observational opportunities will capitalize on the extraordinary progress achieved by models and numerical simulations predicting the properties of the multi-phase ISM to unprecedented accuracy.

By focusing on local galaxies, we can study the baryon cycle to exquisite detail in its full complexity. Through systematic surveys of the star and gaseous content in galaxies at various cosmic epochs, we can characterize the gas cycle throughout cosmic time, and in regimes that are not observed in the local Universe. We can test the impact of luminous, accreting black holes at the center of galaxies, and we can witness the dawn of galaxy formation at the edge of the observable Universe. These new observational constraints are guiding the next generation of galaxy evolution models.

The aim of this conference is to review the latest results on extragalactic studies of the baryon cycle, obtained thanks to IR/(sub-)mm facilities, and in particular with ALMA and JWST, and to state-of-the-art theoretical and numerical models. We will discuss their impact and consequences on our understanding of galaxy evolution from nearby galaxies up to the early Universe.