ESO DOI Service

• Fraser-McKelvie, Amelia [European Southern Observatory (ESO)]
• Barnes, Ashley T. [European Southern Observatory (ESO)]
• Congiu, Enrico [European Southern Observatory (ESO)]
• de Sá-Freitas, Camila [European Southern Observatory (ESO)]

In the past decade, our approach to studying galaxies has undergone a remarkable transformation. By focusing on the most nearby systems, we can now probe the fundamental building blocks of galaxies — molecular clouds, H II regions and star clusters, along with fully resolved galaxy structures such as nuclear stellar discs, bars, and spiral arms — in unprecedented detail. The Galaxy Ecosystems Under the Microscope (GalRes25) workshop brought together over 110 participants from institutes in 18 countries at ESO Headquarters in Garching from 7 to 11 July 2025 to exchange the latest results from these highly resolved studies. Over the course of around 60 talks and 50 posters, participants explored how galaxies assemble their baryonic components, how star formation and feedback regulate their evolution, and how small-scale physics connects to global galactic properties. Sessions on gravitational lensing extended this discussion to the high-redshift Universe, setting the stage for future high-definition studies of galaxies both near and far with the Atacama Large Millimeter/submillimeter Array’s Wideband Sensitivity Upgrade, the Square Kilometre Array, ESO’s Extremely Large Telescope, and upcoming Very Large Telescope instruments such as BlueMUSE and the Multi-conjugate-adaptive-optics-Assisted Visible Imager and Spectrograph (MAVIS).