On the origin of radio-loudness in active galactic nuclei using far-infrared polarimetric observations
To explain the transfer of energy surrounding supermassive black holes (SMBH), most of the theoretical models, if not all, must incorporate magnetic fields (B-fields)—matter rotating around an SMBH must have a B-field to account for the loss of angular momentum. Although this process can explain the dynamics of matter at sub-pc scales, there are still no clear observations of how the matter from the host galaxy, which contains kpc-scale B-fields in close equipartition with the diffuse ISM, feeds SMBHs at 10-100pc-scales. We have observed the signature of magnetically aligned dust grains at distances of a few 10pc at infrared/sub-mm wavelengths in a sample of RL and RQ AGN. We found that RQ AGN are low polarized, while RL AGN are highly polarized at 10-100um. These results are particularly interesting because the dusty torus represents the AGN accretion flow on pc-scales, and this result, besides the radio differences, may be the most telling and dramatic empirical difference between RL vs. RQ AGN. For RL AGN, the B-fields at pc-scales may be able to compress and sustain the dusty torus, which extends the inflow/outflow processes from sub-pc scales to pc-scales and links the inflow and outflow with the dynamics of the host galaxy.