A MILLIMETRE SUBMILLIMETRE POLARIZATION SURVEY OF COMPACT FLAT-SPECTRUM RADIO-SOURCES/

We present the results of the first survey and monitoring study of the linear polarization properties of compact, flat-spectrum radio source s at mm/submm wavelengths and discuss the implications of the inferred magnetic field structure for the emission models involving shock wave s in relativistic jets on subparsec scales. We find significant polari zation in most sources but, in general, the magnetic field on subparse c scales is less well ordered than on parsec scales. We observe no dif ference in polarization properties between the BL Lac objects and comp act hat-spectrum quasars at these wavelengths. Although we find the be haviour of some sources, particularly the most highly polarized, to be very consistent with the predictions of transverse shock-in-jet model s, the detailed behaviour of most objects is not. Conical shock struct ures can more readily explain the observed diverse behaviour of the sa mple, although some degree of bending of the jet may still be necessar y in some cases.