Observing Correlations Between Dark Matter Accretion and Galaxy Growth: II. Testing the Impact of Galaxy Mass, Star Formation Indicator, and Neighbour Colours

TL;DR

This study investigates the relationship between dark matter accretion and galaxy growth, finding no positive correlation and suggesting that internal processes like gas recycling are key drivers of star formation in massive galaxies.

Contribution

It extends previous work by analyzing different galaxy populations, longer-term star formation indicators, and higher-mass galaxies, reinforcing the non-positive correlation between dark matter accretion and star formation.

Findings

No positive correlation between dark matter accretion and star formation activity.

Red and blue neighbour analysis supports non-positive correlation.

Higher-mass galaxies also show no positive correlation.

Abstract

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.