Black Hole Mass Scaling Relations for Spiral Galaxies

Wed 19th September, 2018 @12:00 PM, level 7
Dr Benjamin Davis, Swinburne University

Email:  benjamindavis[at]


For almost a century now, the Hubble-Jeans sequence of galaxies has classified spiral galaxies into morphological classes based on their bulge sizes and the tightness of winding present in their spiral arms. These qualitative morphologies also inform us about the mass of the black hole residing at a spiral galaxy’s centre. Specifically, spiral galaxies that typically possess the largest black holes have large bulges and tightly wound spiral arms. My research focusses on studying spiral galaxy structure and providing accurate, quantitative measurements of their bulge masses and logarithmic spiral arm pitch angles. I will present the details of my recent study of all the known supermassive black holes with directly measured dynamical masses in the literature. For this sample, I have measured their pitch angles and conducted extensive multicomponent decomposition analyses of their surface brightness profiles to determine accurate bulge masses. I will report on the resulting black hole mass scaling relations and discuss their usefulness in predicting unknown black hole masses to generate mass functions and identifying galaxies that might harbour intermediate mass black holes.