1st. Padova – Buenos Aires Workshop on Massive stars and Interacting Binaries
Date:
This study investigates scale relations during early cosmic epochs with a redshift z > 6 using the FirstLight cosmological simulation suite. This suite comprises 300 high-resolution zoom-ins and accurately depicts the reionization of the large-scale intergalactic medium while resolving galaxy properties. We observe that the half-mass radius (rhm) of simulated galaxies shows a moderate increase with stellar mass at M∗ < 108 Modot , followed by a rapid decrease at higher masses. This reduction in galaxy size is predominantly observed in massive galaxies Mstar > 109 Modot , which undergo a phase of rapid compaction and gas depletion. This leads to a contraction of the gaseous component into a compact star-forming phase, subsequently transitioning to central quenching of star formation and forming a compact passive stellar disc. Consequently, we identify positive correlations between galaxy sizes, specific star-formation rates, and gas abundances, marking a transition from diffuse, star-forming regions to compact, quenched structures with extended discs