The roles of environment and interactions on the evolution of red and blue galaxies in the EAGLE simulation
8 February 2024
Astrophysics of Galaxies
Red and blue galaxies have similar environments/clustering until redshift 2
Cold gas/SFR dichotomy exists earlier, not just due to environment
Interacting galaxies have higher SFRs, declining over time
Environmental effects dominate from redshift 2
Blue fraction in pairs drops steeply after redshift 1
Evolution of red and blue galaxies in simulations
This paper analyzes the evolution of red and blue galaxies in the EAGLE simulation from redshift 3 to 0. It finds that differences in local density and clustering strength between the populations are small until redshift 2, after which red galaxies occupy denser regions and cluster more strongly. Large prior cold gas/SFR differences suggest environmental factors alone do not drive the dichotomy. Interacting galaxy pairs have enhanced SFR, declining with time as gas is depleted. An SFR surge around redshift 2 suggests environmental effects begin dominating. The blue fraction in pairs declines substantially from redshift 1, mildly so for isolated pairs with more gas.
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