Microscopic DMBH nuclei evaporate into Axion-Higgs dark energy vacuum particles like ball lightning and small short living earth bound comets seem to do.
Stable DMBH nuclei are growing by "eating" the gravitating ( oscillating Casimir/Axion Higgs) pressure vacuum they don't show standard mass related (Baryonic) inertial effects.
So: DMBHs show emergent gravitating effects ( only Axion/Higgs field vacuum pressure) but reduced- or even none inertial effects.
The result is that
So it seems that there is a dynamic BH selection process in galaxies. How? besides the reduced inertia capacity of BHs we also need a propulsion system for BHs ( plasma tails) for such a Hierarchy process. For plasma tailed BHs see below.
3 Large DMBHs come in the form of primordial GABHs (Galaxy Anchor BHs, out of the splitting Big Bang nucleus) or as central Galaxy BHs gobbling ( eating) much smaller BHs without any trace or LIGO signal .
Conclusion: LIGO sees binary Black Hole mergers with very ( ( 1.sec) short lighthouse effect and the merging of neutron stars with much longer (30 sec) oscillating gravity based lighthouse effects.
see also: https://www.researchgate.net/publication/324390308_Emergent_Pressure_Gravity_by_Dipole_Repeller_Rigid_String_Pressure_the_Origin_of_Non_Inertial_Black_Holes
Proposal for the origin of the BH hierarchy in galaxies.
Large or small DMBHs have the same non inertial potency (zero-Mass), however larger DMBHs are able to create a larger plasma tail for BH propulsion than smaller BHs.
The plasma tail in contrast with the BH has real Baryon mass, so it will be pointing and guided into the center point of the galaxy BH "attraction= singular sided vacuum repulsion" around the giant BH.
As a result pushing BHs away from the galaxy center but with less result and power for small BHs than for larger ones.
Around the central giant galaxy BH ( Sagitarius.) however, the central point of galaxy mass has gone because only emergent Casimir/Axion/Higgs field pressure gravity remains. ( BHs do not emit gravitons).
As a consequence, the pushing BH plasma tails become fluffy without the power to resist the attraction of the central giant BH.
Video of an unstable splitting earth bound micro comet BH.
assumed to be created by Sprite interference far away.
Only the splitting baby comet (video below) is pushed against the high wind direction by a standard plasma tail, because it is supposed to be a "naked" BH without a massive nuclear ice shell.
Magnetic Sprite interference seems to be able to form Quantum Knots called Black Holes, based on the ability of magnetic rigid strings to form two kinds of interconnecting Higgs rings (below) .
The origin: Dual pressure gravity on baryons (graviton and Axion vacuum pressure) and single pressure gravity on black holes (Axion/Higgs vacuum pressure)