Top: Maps of the 8 early-type magnetic stars tentatively detected at 9 GHz (same caption as Fig. 2). Middle and bottom: Maps of the 16 early-type magnetic stars not detected at 9 GHz, gray levels display the pixels map above the 1.5σ threshold. The 3σ level is marked by the light-blue contours. No reliable detection falls within the sky area covered by the FNBW (red ellipses) at the positions where the targets are expected.