Observing Correlations Between Dark Matter Accretion and Galaxy Growth:
  II. Testing the Impact of Galaxy Mass, Star Formation Indicator, and
  Neighbour Colours
  A crucial question in galaxy formation is what role new accretion has in star
formation. Theoretical models have predicted a wide range of correlation
strengths between halo accretion and galaxy star formation. Previously, we
presented a technique to observationally constrain this correlation strength
for isolated Milky Way-mass galaxies at $z\sim 0.12$, based on the correlation
between halo accretion and the density profile of neighbouring galaxies. By
applying this technique to both observational data from the Sloan Digital Sky
Survey and simulation data from the UniverseMachine, where we can test
different correlation strengths, we ruled out positive correlations between
dark matter accretion and recent star formation activity. In this work, we
expand our analysis by (1) applying our technique separately to red and blue
neighbouring galaxies, which trace different infall populations, (2)
correlating dark matter accretion rates with $D_{n}4000$ measurements as a
longer-term quiescence indicator than instantaneous star-formation rates, and
(3) analyzing higher-mass isolated central galaxies with $10^{11.0} <
M_*/M_\odot < 10^{11.5}$ out to $z\sim 0.18$. In all cases, our results are
consistent with non-positive correlation strengths with $\gtrsim 85$ per cent
confidence, suggesting that processes such as gas recycling dominate star
formation in massive $z=0$ galaxies.
