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The Evolving Structure of Galactic Disks

Hugo Martel·Chris Brook·Sean McGee·Brad Gibson·Daisuke Kawata
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Abstract

Observations suggest that the structural parameters of disk galaxies have not changed greatly since redshift 1. We examine whether these observations are consistent with a cosmology in which structures form hierarchically. We use SPH/N-body galaxy-scale simulations to simulate the formation and evolution of Milky-Way-like disk galaxies by fragmentation, followed by hierarchical merging. The simulated galaxies have a thick disk, that forms in a period of chaotic merging at high redshift, during which a large amount of alpha-elements are produced, and a thin disk, that forms later and has a higher metallicity. Our simulated disks settle down quickly and do not evolve much since redshift z~1, mostly because no major mergers take place between z=1 and z=0. During this period, the disk radius increases (inside-out growth) while its thickness remains constant. These results are consistent with observations of disk galaxies at low and high redshift.

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Hugo Martel, Chris Brook, Sean McGee, Brad Gibson, Daisuke Kawata. 2005-09-14. The Evolving Structure of Galactic Disks. https://arxiv.org/abs/astro-ph/0509371

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