ALMA polarimetric follow-up of PACO sources

We present Atacama Large Millimetre/submillimiter Array (ALMA) high sensitivity ({sigma}_P_~0.4mJy) polarimetric observations at 97.5GHz (Band 3) of a complete sample of 32 extragalactic radio sources drawn from the faint Planck-ATCA Co-eval Observations (PACO) sample (b<-75{deg}, compact sources brighter than 200mJy at 20GHz). We achieved a detection rate of ~97 per cent at 3{sigma} (only 1 non-detection). We complement these observations with new Australia Telescope Compact Array (ATCA) data between 2.1 and 35GHz obtained within a few months and with data published in earlier papers from our collaboration.

Adding the co-eval GaLactic and Extragalactic All-sky Murchison widefield array (GLEAM) survey detections between 70 and 230MHz for our sources, we present spectra over more than 3 decades in frequency in total intensity and over about 1.7 decades in polarization. The spectra of our sources are smooth over the whole frequency range, with no sign of dust emission from the host galaxy at mm wavelengths or of a sharp high frequency decline due, for example, to electron ageing.