The black hole mass - spheroid luminosity relation

The differing Mbh-Luminosity relations presented in McLure a correction for dust attenuation in the bulges of disc galaxies; the identification of lenticular galaxies previously treated as elliptical galaxies; and application of the same (Y|X) regression analysis. These adjustments result in relations which now predict similar black hole masses. The optimal K-band relation is log (Mbh/Mₛun) = -0. 37 (+/-0. 04) MK +24 + 8. 29 (+/-0. 08), with a total (not intrinsic) scatter in log Mbh equal to 0. 33 dex. This level of scatter is similar to the value of 0. 34 dex from the Mbh-sigma relation of Tremaine et al. and compares favourably with the value of 0. 31 dex from the Mbh-n relation of Graham & Driver. Using different photometric data, consistent relations in the B- and R-band are also provided, although we do note that the small (N=13) R-band sample used by Erwin et al. is found here to have a slope of -0. 30 (+/-0. 06) and a total scatter of 0. 31 dex. Performing a symmetrical regression on the larger K-band sample gives a slope of -0. 40, implying Mbh ~ L^1. 00. Implications for galaxy-black hole coevolution, in terms of dry mergers, are briefly discussed, as are predictions for intermediate mass black holes. Finally, as previously noted by Tundo et al. , a potential bias in the galaxy sample used to define the Mbh-L relations is shown and a corrective formula provided.