Description
The relative abundance of the red and blue galaxy populations has been found to vary with stellar mass and environment. We explored the effect of environment considering different types of measurements using a sample of 50,000 galaxies with $0.05 < z < 0.18$. We studied the dependence of the fraction of red galaxies on different measures of the local environment as well as the large-scale `geometric’ environment defined by density gradients in the surrounding cosmic web. By comparing the different environmental densities, no density measurement fully explains the observed environmental red fraction variation, suggesting the different measures of environmental density contain different information. We tested whether the local environmental measures, when combined together, can explain all the observed environmental red fraction variation. The geometric environment has a small residual effect, and this effect is larger for voids than any other type of geometric environment. This could provide a test of the physics applied to cosmological-scale galaxy evolution simulations as it combines large-scale effects with local environmental impact.
