Why Massive Black Holes are Small in Disk Galxies

摘要: A potential mechanism is proposed to account for the fact that supermassive black holes (SMBHs) in disk galaxies appear be smaller than those elliptical same luminosity range. We consider formation of SMBHs by radiation drag (Poynting-Robertson effect), which extracts angular momentum from interstellar matter and thereby drives mass accretion onto a galactic center. In particular, we quantitatively scrutinize efficiency galaxy composed bulge disk, elucidate relation between final SMBH bulge-to-disk ratio galaxy. As result, it found BH-to-galaxy ratio, $M_{\rm BH}/M_{\rm galaxy}$, decreases with due effects geometrical dilution opacity, reduced maximally two orders magnitude, resulting galaxy}\approx 10^{-5}$. contrast, if only components are focused, BH-to-bulge becomes bulge}\approx 10^{-3}$, similar galaxies. Thus, turns out primarily correlates bulge, not consistently observational data.