The radio spectrum of Algol-type systems: RZ Cassiopeiae

We present multifrequency radio observations of the Algol-type binary syste m RZ Cas, performed in different epochs from 1991 October to 1992 April. Du ring this period the system shows variability in the radio flux that cannot be attributed to geometrical effects due to a partial eclipse of the radio source. Instead, differences between radio spectra can be reproduced assuming a cor e-halo morphology for the radio source, where physical conditions vary as a consequence of magnetic activity. Almost simultaneous X-ray observations, carried out by other authors, allow to further constrain the physical param eters of the radio emitting region and are consistent with a co-spatial mod el for the X-ray and radio emitting source.