We use KiDS weak lensing data to measure variations in mean halo mass as a function of several key galaxy properties ( namely : stellar colour , specific star formation rate , Sérsic index , and effective radius ) for a volume-limited sample of GAMA galaxies in a narrow stellar mass range ( M _ { * } \sim 2 – 5 \times 10 ^ { 10 } M _ { \odot } ) .
This mass range is particularly interesting , inasmuch as it is where bimodalities in galaxy properties are most pronounced , and near to the break in both the galaxy stellar mass function and the stellar-to-halo mass relation ( SHMR ) .
In this narrow mass range , we find that both size and Sérsic index are better predictors of halo mass than colour or SSFR , with the data showing a slight preference for Sérsic index .
In other words , we find that mean halo mass is more strongly correlated with galaxy structure than either stellar populations or star formation rate .
These results lead to an approximate lower bound on the dispersion in halo masses among \log M _ { * } \approx { 10.5 } galaxies : we find that the dispersion is \gtrsim 0.3 dex .
This would imply either that offsets from the mean SHMR are very tightly coupled to size/structure , or that the dispersion in the SHMR is larger than past results have suggested .
Our results thus provide new empirical constraints on the relationship between stellar and halo mass assembly at this particularly interesting mass range .