| Abstract: | In this talk, I will present revised scaling relations of masses (MBH) of Supermassive Black Holes (BHs) with galaxy and bulge properties, focusing on bulge masses (Mbul) in low-mass and late-type galaxies where the bulge is only a minor component. By means of HST/WFC3 optical and near-infrared data, we analyzed BH host galaxies with MBH precisely known by their nuclear Megamaser emission. Due to the superior image quality and detailed analysis techniques, we are able to decompose these complex systems, to isolate and parametrize their likely classical bulges apart from pseudobulge and other disk-like components. Thus we are able to test whether BH (AGN) feedback is effective in and primarily associated with (classical) bulges, irrespective of BH host morphology at large. However, we do not find a particularly tight relation between these systems’ MBH and Mbul, questioning the universal distinguished role of (classical) bulges in a putative co-evolution with their BHs. We also note an apparent offset to lower MBH on average, when compared to the MBH - Mbul relation of early-type systems. Finally, the log-slope of the augmented MBH - Mbul relation is smaller than unity, in contrast to predictions of standard feedback scenarios. Our results demonstrate how nuclear Megamasers are able to significantly improve the characterization of BH scaling relations in this otherwise hard-to-access and undersampled regime of low masses and late host morphologies, and highlight our need for a more detailed and comprehensive theory of the formation and growth of BHs. |
