A Correlation between Galaxy Light Concentration and Supermassive Black Hole Mass

Abstract

We present evidence for a strong correlation between the concentration of bulges and the mass of their central supermassive black hole (M_bh)-more concentrated bulges have more massive black holes. Using C_re(1/3) from Trujillo, Graham, & Caon as a measure of bulge concentration, we find that log(M_bh/M_solar)=6.81(+/- 0.95)C_re(1/3)+5.03+/-0.41. This correlation is shown to be marginally stronger (Spearman's r_s=0.91) than the relationship between the logarithm of the stellar velocity dispersion and logM_bh (Spearman's r_s=0.86) and has comparable or less scatter (0.31 dex in logM_bh, which decreases to 0.19 dex when we use only those galaxies whose supermassive black hole radii of influence are resolved and we remove one well-understood outlying data point).