Dependence of dust obscuration on star formation rates in galaxies

Many investigations of star formation rates (SFRs) in galaxies have explored details of dust obscuration, with a number of recent analyses suggesting that obscuration appears to increase in systems with high rates of star formation. To date, these analyses have been primarily based on nearby (z less than or equal to 0.03) or UV-selected samples. Using 1.4 GHz imaging and optical spectroscopic data from the Phoenix Deep Survey, the SFR-dependent obscuration is explored. The use of a radio-selected sample shows that previous studies exploring SFR-dependent obscurations have been biased against obscured galaxies. The observed relation between obscuration and SFR is found to be an unsuitable obscuration measure for individual galaxies. Nevertheless, it is shown to be successful as a first-order correction for large samples of galaxies when no other measure of obscuration is available, out to intermediate redshifts ( z approximate to 0.8).