Open Access Online Journal on Astronomy and Astrophysics Acta Astrophysica Taurica www.astrophysicatauricum.org Acta Astrophys. Tau. 3(1), 39–43 (2022) doiȷ10.«1059/aat.vol«.iss1.pp«9-»« The morphology-dependent black hole–host galaxy correlations: a consequence of physical formation processes Nandini Sahu 1,2 , Alister W. Graham 2 , and Benjamin L. Davis 3 1 OzGrav-Swinburne, Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, VIC «122, Australia e-mailȷ nsahu@swin.edu.au 2 Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, VIC «122, Australia e-mailȷ agraham@swin.edu.au 3 Center for Astro, Particle, and Planetary Physics (CAP «), New York University Abu Dhabi e-mailȷ ben.davis@nyu.edu Submitted on November 2«, 2021 ABSTRACT For decades, astronomers have been investigating how the central supermassive black hole (BH) may govern the host galaxy’s properties and vice versa. Our work adds another step to this study. We have performed state-of-the- art 2D modeling and multi-component photometric decompositions of the largest-to-date sample of galaxies with dynamically-measured black hole masses (  BH ). The multi-component decomposition allows us to accurately extract the bulge (spheroid) stellar luminosity/mass and structural parameters (also for other galaxy components) and provides detailed galaxy morphologies. We investigated the correlations between  BH and various host galaxy properties, including the bulge (  ∗, sph ) and total galaxy (  ∗, gal ) stellar masses discussed here. Importantly, we analyzed the role of galaxy morphology in these correlations. Our work reveals that the BH scaling relations depend on galaxy morphology and thus depend on the galaxy’s formation and evolution physics. Here we discuss that in the  BH – ∗, sph diagram, early-type galaxies (ETGs) with a disk, ETGs without a disk, and late-type galaxies (LTG-spirals) defne distinct relations, with quadratic slopes but diferent zero-points. We also review the  BH – ∗, gal relation, where ETGs and LTGs defne diferent relations. Notably, the existence of the  BH – ∗, gal relations enables one to quickly estimate  BH in other galaxies without going through the multi-component decomposition process to obtain  ∗, sph . The fnal morphology-dependent black hole scaling relations provide tests for morphology-aware simulations of galaxies with a central BH and hold insights for BH-galaxy co-evolution theories based on BH accretion and feedback. Key words: Early-type galaxies (»29) – Galaxy evolution (59») – Galaxy spheroids (20«2) – Late-type galaxies (907) – Scaling relations (20«1) – Supermassive black holes (166«) 1 Introduction Almost all galaxies in the Universe are expected to host a supermassive black hole (BH) at their center, which is thought to co-evolve with the host galaxy (Lynden-Bell, 1969; Lynden-Bell and Rees, 1971). Plausibly, a galaxy may control the central BH’s mass growth as the BH feeds on it. Conversely, the BH feedback is invoked to suggest that BH outfows expel out the gas content of the host galaxy, thereby shut down the star formation and regulate the galaxy’s stel- lar content and other properties (e.g., Silk and Rees, 1998; Fabian, 1999). The observed correlations between BH mass and the host galaxy properties hold crucial insights for under- standing this co-evolution. A review on various past eforts for establishing the correlation between BH mass and host galaxy properties (e.g., bulge mass, velocity dispersion, etc.), starting with the frst studies and subsequent crucial advance- ments until 2016 can be found in Graham (2016). The largest-to-date sample of galaxies with directly- measured black hole masses (  BH ) currently numbers to 1»5 (listed in Sahu et al., 2019b). The direct BH mass measure- ment methods are proper motion, stellar and gas dynamical modeling, megamaser kinematics, and recent direct imag- ing. An informative review on the frst four methods can be found in Ferrarese and Ford (2005), also see Peterson (201»), and the details about the recent direct-imaging technique can be found in Event Horizon Telescope Collaboration et al. (2019). Savorgnan and Graham (2016), Davis et al. (2019), and Sahu et al. (2019a) collectively performed state-of-the-art two-dimensional modeling and multi-component decompo- sition of the host galaxy images of 12« of these galaxies. We did not simply add Sérsic functions (Sérsic, 196«, 1968), but ft for disks, bars, ansae, rings, etc., as required and revealed through both images and kinematics. The multi- component decomposition enabled us to extract the lumi-