English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Recent results from spectroscopic and astrometric surveys of nearby starssuggest that the stellar disk of our Milky Way (MW) was formed quite early,within the first few billion years of its evolution. Chemokinematic signaturesof disk formation in cosmological zoom-in simulations appear to be in tensionwith these data, implying that MW-like disk formation is delayed insimulations. We investigate the formation of galactic disks using arepresentative sample of MW-like galaxies from the cosmological-volumesimulation TNG50. We find that on average MW-mass disks indeed form later thanthe local data suggest. However, their formation time and metallicity exhibit asubstantial scatter, such that $\sim$10% of MW-mass galaxies form disks early,similar to the MW. Thus, although the MW is unusual, it is consistent with theoverall population of MW-mass disk galaxies. The direct MW analogs assemblemost of their mass early, $\gtrsim 10$ Gyr ago, and are not affected bydestructive mergers after that. In addition, these galaxies form their disksduring the early enrichment stage when the interstellar medium metallicityincreases rapidly, with only $\sim$25% of early-forming disks being asmetal-poor as the MW was at the onset of disk formation, [Fe/H] $\approx -1.0$.In contrast, most MW-mass galaxies either form disks from already enrichedmaterial or experience late destructive mergers that reset the signatures ofgalactic disk formation to later times and higher metallicities. Finally, wealso show that earlier disk formation leads to more dominant rotationallysupported stellar disks at redshift zero.

Formation of Galactic Disks I: Why Did the Milky Way's Disk Form Unusually Early?