Defining the (Black Hole)-spheroid connection with the discovery of morphology-dependent substructure in the MBH-nsph and MBH-Re,sph Diagrams: New tests for advanced theories and realistic simulations

For 123 local galaxies with directly measured black hole masses (MBH), we provide the host spheroid's Sérsic index (nsph), effective half-light radius (Re,sph), and effective surface brightness (μe), obtained from careful multicomponent decompositions, and we use these to derive the morphology-dependent MBH-nsph and MBH-Re,sph relations. We additionally present the morphology-dependent M∗,sph-nsph and M∗,sph-Re,sph relations. We explored differences due to early-type galaxies (ETGs) versus late-type galaxies (LTGs), Sérsic versus core-Sérsic galaxies, barred versus non-barred galaxies, and galaxies with and without a stellar disk. We detect two different MBH-nsph relations due to ETGs and LTGs with power-law slopes 3.95 ± 0.34 and 2.85 ± 0.31. We additionally quantified the correlation between MBH and the spheroid's central concentration index, which varies monotonically with the Sérsic index. Furthermore, we observe a single, near-linear M∗,sph-Re,sph1.08±0.04 relation for ETGs and LTGs, which encompasses both classical and alleged pseudobulges. In contrast, ETGs and LTGs define two distinct MBH-Re,sph relations with Drms BH ∼ 0.60 dex (cf. 0.51 dex for the MBH-σ relation and 0.58 dex for the MBH-M∗,sph relation), and the ETGs alone define two steeper MBH-Re,sph relations, offset by 1dex in the logMBH direction, depending on whether they have a disk or not and explaining their similar offset in the MBH-M∗,sph diagram. This trend holds using 10%, 50%, or 90% radii. These relations offer pivotal checks for simulations trying to reproduce realistic galaxies, and for theoretical studies investigating the dependence of black hole mass on basic spheroid properties.