As the most abundant element in the Universe, hydrogen is an ubiquitous tracer of structures at various scales and plays a fundamental role in galaxy formation. Accretion of hydrogen from the intergalactic medium (IGM) feeds galaxies with the raw material necessary for the formation of stars. Environmental effects and complex internal mechanisms, such as supernovae or AGN feedback, affect the evolution cycle of hydrogen and consequently the physical properties and appearance of galaxies. Observations of hydrogen in its various forms (atomic, ionised or molecular), along with refined models and simulations, are essential to better assess the role of hydrogen in the formation and evolution of galaxies. This conference will bring together observers and theorists to review our current understanding in the field, and discuss the main science questions that can be addressed in the pre-SKA era.
The scientific topics covered at this conference will include:
- Evolution of hydrogen in the cosmological context
- Environmental effects and the role of groups and clusters
- Outflows, accretion and the IGM
- The ISM and the link with star formation
- The Milky Way and the Local Group
- State-of-the-art surveys.