Constraints on the radio loud/radio quiet dichotomy from the fundamental plane

Understand

The fundamental plane for black hole activity constitutes a tight correlation between jet power, X-ray luminosity, and black hole mass.

• Under the assumption that a Blandford-Znajek-type mechanism, which relies on black hole spin, contributes non-negligibly to jet production, the sufficiently small scatter in the fundamental plane shows that black hole spin differences of $\mid$$\Delta$a$\mid \sim$1 are not typical among the active galactic nuclei population.
• If $-$ as it seems $-$ radio loud and radio quiet objects are both faithful to the fundamental plane, models of black hole accretion in which the radio loud/radio quiet dichotomy is based on a spin dichotomy of a$\sim$1/a$\sim$0, respectively, are difficult to reconcile with the observations.
• We show how recent theoretical work based on differences in accretion flow orientation between retrograde and prograde, accommodates a small scatter in the fundamental plane for objects that do have non-negligible differences in black hole spin values.