Disc galaxies since z=1 sizes

Although the half-light radius has many advantages for structurally parameterising galaxies, it does not provide a measure of the global extent of the objects, but only an indication of the size of the region containing the innermost 50% of the galaxy's light. Therefore, the observed mild evolution of the effective radius of disc galaxies with cosmic time is conditioned by the evolution of the central part of the galaxies rather than by the evolutionary properties of the whole structure.

Expanding on recent works by Trujillo et al. (2020MNRAS.493...87T, Cat. J/MNRAS/493/87) and Chamba et al. (2022A&A...667A..87C), we studied the size evolution of disc galaxies using the radial location of the gas density threshold for star formation as a size indicator. As a proxy to evaluate this quantity, we used the radial position of the truncation (edge) in the stellar surface mass density profiles of galaxies.