We present new radio continuum observations of two dwarf starburst galaxies , NGC 3125 and NGC 5408 , with observations at 4.80GHz ( 6cm ) and 8.64GHz ( 3cm ) , taken with the Australia Telescope Compact Array ( ATCA ) .
Both galaxies show a complex radio morphology with several emission regions , mostly coincident with massive young star clusters .
The radio spectral indices of these regions are negative ( with \alpha \sim - 0.5 - -0.7 ) , indicating that the radio emission is dominated by synchrotron emission associated with supernova activity from the starburst .
One emission region in NGC 5408 has a flatter index ( \alpha \sim - 0.1 ) indicative of optically thin free-free emission , which could indicate it is a younger cluster .
Consequently , in these galaxies we do not see regions with the characteristic positive spectral index indicative of optically obscured star-formation regions , as seen in other dwarf starbursts such as Hen 2-10 .