Previous studies have shown that galaxies with minor companions exhibit an elevated star formation rate .
We reverse this inquiry , constructing a volume-limited sample of \sim L ^ { \star } ( M _ { r } \leq - 19.5 + 5 \log { h } ) galaxies from the Sloan Digital Sky Survey that are isolated with respect to other luminous galaxies .
Cosmological simulations suggest that 99.8 % of these galaxies are alone in their dark matter haloes with respect to other luminous galaxies .
We search the area around these galaxies for photometric companions .
Matching strongly star forming ( { EW ( H \alpha ) } \geq 35 Å ) and quiescent ( { EW ( H \alpha ) } < 35 Å ) samples for stellar mass and redshift using a Monte Carlo resampling technique , we demonstrate that rapidly star-forming galaxies are more likely to have photometric companions than other galaxies .
The effect is relatively small ; about 11 % of quiescent , isolated galaxies have minor photometric companions at radii \leq 60 kpc h ^ { -1 } kpc while about 16 % of strongly star-forming ones do .
Though small , the cumulative difference in satellite counts between strongly star-forming and quiescent galaxies is highly statistically significant ( P _ { KS } = 1.350 \times 10 ^ { -3 } ) out to to radii of \sim 100 h ^ { -1 } kpc .
We discuss explanations for this excess , including the possibility that \sim 5 \% of strongly star-forming galaxies have star formation that is causally related to the presence of a minor companion .