  Black hole accretion and jet formation have long been thought to be scale
invariant. One empirical relation suggesting scale invariance is the
Fundamental Plane of Black Hole activity, which is a plane in the space given
by black hole mass and the radio/X-ray luminosities. We search for an
alternative version of this plane using the luminosity of [OIII] emission line
instead of X-ray luminosity. We use a complete sample of 39 supermassive black
holes selected from the Palomar Spectroscopic Survey with available radio and
optical measurements and information on black hole mass. A sample of stellar
mass X-ray binaries has also been included to examine if physical processes
behind accretion is universal across the entire range of black hole mass. We
present the results of multivariate regression analysis performed on the AGN
sample and show that the sample stretches out as a plane in the 3D logarithmic
space created by bolometric luminosity, radio luminosity and black hole mass.
We reproduce the established Fundamental Plane of Black Hole activity in
X-rays. We show that this plane can be obtained with the supermassive black
hole sample alone and the X-ray binaries agrees to the found relation. We also
discuss radio loudness of various classes of low-luminosity AGN in view of our
fundamental plane.
