How relevant is the torus activity/geometry for the TeV gamma-rays emitted in the jet of M87?

Abstract

Motivated by unification schemes of active galactic nuclei, we review evidence for the existence of a small-scale dust torus in M87, a Fanaroff-Riley Class I radio galaxy. Since there is no direct evidence of any thermal emission from its torus we consider indirect evidence, such as BLR activity and ageing arguments to model the cold dust structure of M87. In the context of the jet -- accretion disk -- torus symbiosis we discuss the interactions of GeV and TeV gamma-rays produced in the jet of M87 with the infrared radiation fields external to the jet, produced by a less active torus. A thin and cold torus with less defined outer boundaries could still posses problems to some of the TeV emission from the jet.