The Local and Large Scale Environment of Different Types of AGN

We study the local and large scale environment of different types of AGN defining the overdensity distribution of optical galaxies within different distances. Moreover, we investigate the activity of their close companions in order to test different models of the triggering mechanism of AGN. According to the Unification Scheme, the AGN phenomenology can be explained by a single type of AGN having different inclinations of their dust torus with respect to the observer’s line of sight. However, an evolutionary scenario, which starts with a circumnuclear starburst phase, with the nucleus subsequently being obscured by dust (Type II AGN) and eventually ending as a Type I AGN, suggests that the appearance of an AGN depends also on its current evolutionary stage. Possible indications of different types of AGN residing in denser local environment, compared to other types, would support the merger scenario, and therefore, the obscuration of the central region and the possible activation of the central black hole. With our current study we wish to investigate whether the environment of different types of AGN is similar, since this is the expectation of the Unification paradigm or whether it is different, a fact that could support the evolutionary scenario. We find differences in the environment of different AGN types and therefore, conclude that the environment indeed affects the spectral type of galaxies.