  The connection between galaxy star formation rate (SFR) and dark matter (DM)
is of paramount importance for the extraction of cosmological information from
next generation spectroscopic surveys that will target emission line star
forming galaxies. Using publicly available mock galaxy catalogs obtained from
various semi-analytic models (SAMs) we explore the SFR-DM connection in
relation to the speed-from-light method (Feix et al. 2016) for inferring the
growth rate, $f$, from luminosity/SFR shifts. Emphasis is given to the
dependence of the SFR distribution on the environment density on scales of
10s-100s Mpc. We show that the application of the speed-from-light method to an
Euclid-like survey is not biased by environmental effects. In all models, the
precision on the measured $\beta=f/b$ parameter is $\sigma_\beta < 0.17$ at
$z=1$. This translates into errors of $\sigma_f \sim 0.22$ and
$\sigma_{(f\sigma_8)}\sim 0.1$, without invoking assumptions on the mass power
spectrum. These errors are in the same ballpark as recent analyses of the
redshift space distortions in galaxy clustering. In agreement with previous
studies, the bias factor, $b$ is roughly a scale-independent, constant function
of the SFR for star forming galaxies. Its value at $z=1$ ranges from $1.2$ to
$1.5$ depending on the SAM recipe. Although in all SAMs denser environments
host galaxies with higher stellar masses, the dependence of the SFR on the
environment is more involved. In most models the SFR probability distribution
is skewed to larger values in denser regions. One model exhibits an inverted
trend where high SFR is suppressed in dense environment.
