It is in debate that whether a link between galaxy formation and central black hole growth exists, and if yes, how the link is established. With SDSS and WISE data, a systematic comparison between optical and IR selected AGNs is performed. The emissivity distributions from [OIII] and mid-IR radiation are very similar, supporting the validity of the standard AGN unification model. It also confirms previous result that strong AGNs are usually hosted by galaxies with young stellar population. Yet different from [OIII] narrow line emission, the IR torus emission is found to be associated with excessive number of close companions when the clustering effect of host star formation is carefully controlled, showing evidence of direct AGN-host connection via galaxy interactions.
