Shallow cores in bright , massive galaxies are commonly thought to be the result of scouring of stars by mergers of binary supermassive black holes .
Past investigations have suggested correlations between the central black hole mass and the stellar light or mass deficit in the core , using proxy measurements of M _ { BH } or stellar mass-to-light ratios ( \Upsilon ) .
Drawing on a wealth of dynamical models which provide both M _ { BH } and \Upsilon , we identify cores in 23 galaxies , of which 20 have direct , reliable measurements of M _ { BH } and dynamical stellar mass-to-light ratios ( \Upsilon _ { \star, { dyn } } ) .
These cores are identified and measured using Core-Sérsic model fits to surface brightness profiles which extend out to large radii ( typically more than the effective radius of the galaxy ) ; for approximately one fourth of the galaxies , the best fit includes an outer ( Sérsic ) envelope component .
We find that the core radius is most strongly correlated with the black hole mass and that it correlates better with total galaxy luminosity than it does with velocity dispersion .
The strong core-size– M _ { BH } correlation enables estimation of black hole masses ( in core galaxies ) with an accuracy comparable to the M _ { BH } – \sigma relation ( rms scatter of 0.30 dex in \log M _ { BH } ) , without the need for spectroscopy .
The light and mass deficits correlate more strongly with galaxy velocity dispersion than they do with black hole mass .
Stellar mass deficits span a range of 0.2–39 M _ { BH } , with almost all ( 87 % ) being < 10 M _ { BH } ; the median value is 2.2 M _ { BH } .