Johan H. Knapen Livres

This book features invited reviews by leading experts on the understudied outskirts of galaxies, a field rich with information about galaxy origins and early evolution. These faint regions present challenges for observation but are crucial for addressing key issues such as gaseous and satellite accretion, radial migration, and merging. Published alongside the conclusion of the four-year DAGAL project, an EU-funded training network, and a major international conference held in March 2016 in Toledo, the book encapsulates the insights and discussions from both the project and the event. The reviews cover modern observations of the outer regions of our Galaxy and other galaxies across the local and high-redshift Universe, examining disks, haloes, streams, and accretion through deep imaging and spectroscopy. They guide readers through various formation and evolution scenarios for galaxies while focusing on major open questions in the field and potential future research directions. This work serves as an accessible entry point for graduate students and non-specialists, while also acting as a valuable reference for researchers in this emerging area of study.