ALMABO19

The first conference in the ALMABO series

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 circum-galactic environment, thus completing the so-called `baryon cycle'. Understanding this process and its dependence on different galaxy properties and cosmic times is one of the key-question of modern astrophysics and is very challenging, given the complexity and interplay of the physical mechanisms involved and the difficulty to be observed the interstellar gas in distant galaxies.

The advent of the power of the Atacama Large Millimeter Array (ALMA) and the upgraded capabilities of other sub-mm/mm facilities are now opening a complete new window of the baryon cycle. On one hand, local galaxies are exploited as 'laboratories' where the interstellar medium is studied down to molecular cloud scales and the physical processes can be investigated in detail. On the other hand, thanks to the unprecedented sensitivities of the new facilities, systematic surveys of the gaseous content in high redshift galaxies are starting to characterize the gas cycle throughout cosmic time. Dedicated observations have revealed gas in the most distant galaxies, all the way to the reionization epoch, and have started to dissect the interplay between luminous active galactic nuclei and their host galaxy. These new observational constraints are guiding the next generation of galaxy evolution models.

The aim of this conference was 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 to discuss their impact and consequences on our understanding of galaxy evolution from nearby galaxies up to the early Universe.