Observations of a radio jet in the Seyfert galaxy Markarian 3.

The nucleus of the Seyfert 2 galaxy Markarian 3 has been observed with MERLIN at wavelengths of 73 and 18 cm with angular resolution of 1 and 0.25 arcsec respectively. In contrast to earlier observations, which suggested a double-lobe structure, the source is shown to have a highly elongated structure 2.5 arcsec in extent, which the authors interpret as a radio jet emerging from an unresolved core. They suggest that the low-frequency turnover in the radio spectrum may be due to free-free absorption by ionized gas in the forbidden-line region. Equipartition arguments suggest that the pressure of the relativistic radio-emitting plasma is too high for this plasma to be confined by the thermal pressure of the gas in the forbidden-line region.