Revealing Hidden Substructures in the M _BH-σ Diagram, and Refining the Bend in the L-σ Relation

Using 145 early- and late-type galaxies (ETGs and LTGs) with directly measured supermassive black hole masses, M _BH, we build upon our previous discoveries that: (i) LTGs, most of which have been alleged to contain a pseudobulge, follow the relation M_BH ∝ M_∗,sph ^2.16±0.32 and (ii) the ETG relation M_BH ∝ M_∗,sph ^1.27±0.07 is an artifact of ETGs with/without disks following parallel M_BH ∝ M_∗,sph ^1.9±0.2 relations that are offset by an order of magnitude in the M _BH direction. Here, we searched for substructure in the diagram of M _BH versus central velocity dispersion σ, using our recently published multi-component galaxy decompositions, by investigating divisions based on the presence of a depleted stellar core (major dry merger), a disk (minor wet/dry merger, gas accretion), or a bar (evolved unstable disk). The Sérsic and core-Sérsic galaxies define two distinct relations: M_BH ∝ σ^5.75±0.34 and M_BH ∝ σ^8.64±1.10, with Δ_rms|BH and 0.46 dex, respectively. We also report on the consistency with the slopes and bends in the galaxy luminosity (L)-σ relation due to Sérsic and core-Sérsic ETGs, and LTGs that all have Sérsic light profiles. Two distinct relations (superficially) reappear in the M _BH-σ diagram upon separating galaxies with/without a disk (primarily for the ETG sample), while we find no significant offset between barred and non-barred galaxies, nor between galaxies with/without active galactic nuclei. We also address selection biases purported to affect the scaling relations for dynamically measured M _BH samples. Our new M _BH-σ relations, dependent on morphological type, more precisely estimate M _BH in other galaxies, and hold implications for galaxy/black hole coevolution theories, simulations, feedback, the pursuit of a black-hole fundamental plane, and calibration of virial f-factors for reverberation mapping.