As galaxies form and evolve in the Universe, they leave behind a complex trail of ultra-faint stars and gas in their outskirts. This faint material holds clues to the growth and accretion history of galaxies. In this colloquium, we present some of the deepest images of the faint universe, of dwarf and massive galaxies, as seen in X-ray, optical and radio wavelengths. We discuss how these images help us understand the key physical and environmental processes such as star formation, feedback and mergers that drive the growth of galaxies big and small. These results demonstrate the importance of preserving low surface brightness structure in the next generation of surveys from Euclid, Rubin-LSST, Roman and SKA in order to further our understanding of galaxies across the Universe.

Location: Department of Galaxies, Room 101, Spořilov

Magnetised bubbles pervade the interstellar medium across a vast range of scales, from individual supernova remnants (SNRs) to the superbubbles they collectively inflate. We present two complementary 3D magnetohydrodynamic studies tracing this hierarchy from its smallest building blocks to its most prominent local example. We simulate SNRs expanding into a non-homogeneous, magnetised two-phase medium, obtaining complex magnetic field configurations in their interiors. Strongly magnetised remnants develop magnetically confined hot cavities surrounded by a diffuse magnetised halo, and remain orders of magnitude more X-ray luminous than their weakly magnetised counterparts. We then extend our study to larger scales, simulating the Local Bubble: a superbubble encasing the Solar neighbourhood, whose expansion has been driven by numerous supernovae. We characterise its turbulent interior magnetic field and its amplification in the shell, while also modelling neighbouring superbubbles and SNRs within 1 kpc of the Sun. Together, these parsec- to kiloparsec-scale frameworks give us insights on the coupling between magnetic fields and stellar feedback, from individual remnants to the large-scale cavities structuring the local interstellar medium.

Location: Spořilov - Lecture Room 101