MONITORING OF AO-0235+164 DURING A FAINT STATE

We present the results of the optical and radio monitoring of the BL L ac object AO 0235+164 during a faint state. In both optical and radio bands the source has been observed at the faintest ever recorded level s, reaching V = 19.80 and F-22GHz = 0.34 Jy. In the optical bands we s till see variability with amplitudes up to 1.5 magnitudes on timescale s from days to weeks. The radio variability is less dramatic, but in g eneral follows the optical behaviour. A correlation between general tr ends in the optical and radio behaviour of AO 0235+164 may be recogniz ed in the data from the present monitoring as well as in the historica l light curves, suggesting a ''base'' mechanism responsible for the em ission at both frequencies. A good candidate is a synchrotron process in the relativistic jet. Optical flares with no corresponding radio co unterparts have been observed too. These events may be interpreted in terms of microlensing by a foreground galaxy.