Speaker

Elena Arjona-Gálvez: 

Instituto de Astrofísica de Canarias

Abstract

The measure of galaxies has always been an important matter in the astrophysics community as it strongly correlates with the formation and evolution of those objects. Several ways of defining the outskirts of a galaxy have been proposed throughout the years using the concentration light or isophote densities. However, those definitions were based on the limitations of the current observations at the moment but without a proper physical definition. Recent observational studies propose a new definition to establish the sizes of the galaxies, taking advantage of the precision of the new multiwavelength deep imaging surveys. They use the stellar mass density contour at 1 M⊙pc−2 as a proxy for this density threshold for star formation. In this talk, we show that several state-of-art hydrodynamical simulations strongly agree with the proposed stellar mass-size relation, finding the same behaviour with a significant low scatter in the smaller and more massive range and being independent of the redshift and simulations used. We propose this relation as a consistent proxy for simulations to measure not only the outskirts of the galaxies at z=0 but also throughout the whole galaxy's evolution.

Scientific theme

Size galaxies - Galaxy evolution - Galaxy formation - simulations