A DEEP LAMBDA-20 CM RADIO-CONTINUUM SURVEY OF M-31

We present a survey of the total and linearly polarized radio continuu m emission of the Andromeda galaxy at 20 cm wavelength with the VLA-D array. 7 fields were observed with 45 '' angular resolution. The missi ng large-scale total emission observed with the Effelsberg telescope w as inserted. This survey is the most sensitive radio continuum survey of M 31 so far and the first one in linear polarization with the VLA. The total emission of M 31 comes from extended regions and point sourc es. Both components are concentrated in the bright ''ring'' of maximum star formation at about 10 kpc radius. Nearly half of the extended em ission emerges from numerous filamentary features which are typically a few arcminutes long (similar or equal to 600 pc). In the field of M 31, 36 linearly polarized background sources were detected. The smalle st degrees of polarization occur on the centre of the ''ring'' where t he total emission is highest, hence on the spiral arms as delineated b y H alpha emission and OB associations. The distribution of polarizati on angles reveals coherent features of typically 1 kpc in extent, some of which show a relation to an OB association.