Low radio-derived star formation rates in z < 0.5 gamma-ray burst host galaxies

We present 5.5- and 9.0-GHz observations of five gamma-ray burst host galaxies at z < 0.5, taken using the Australia Telescope Compact Array. We determine tight constraints on the radio continuum flux of four sources (GRB hosts 060218, 060614, 020819 and 990712) and detect a fifth source, the host of GRB 031203, with a flux density Fν(5.50 GHz) = 216 ± 50 μJy. We discuss the star formation rates of all five sources. Our radio-derived star formation rates (and upper limits) are largely consistent with those derived from optical observations, suggesting either that there is little dust-obscured star formation in these sources, or that their starbursts are too young to have established representative radio continuum emission