Fundamental Planes, and the Barless Mbh-σ Relation, for Supermassive Black Holes

The residuals about the standard Mbh-σ relation correlate with the effective radius, absolute magnitude, and Sérsic index of the host bulge. Although, it is noted here that the elliptical galaxies do not partake in such correlations. Moreover, it is revealed that barred galaxies (with their relatively small, faint, and low stellar concentration bulges) can deviate from the Mbh-σ relation by δ logMbh ≈ −0.5 to −1.0 dex (their σ values are too large) and generate much of the aforementioned correlations. Removal of the seven barred galaxies from the Tremaine et al. set of 31 galaxies gives a “barless Mbh-σ” relation with an intrinsic scatter of 0.17 dex (cf. 0.27 dex for the 31 galaxies) and a total scatter of 0.25 dex (cf. 0.34 dex for the 31 galaxies). The introduction of a third parameter does not reduce the scatter. Furthermore, removal of the barred galaxies, or all the disk galaxies, from an expanded and updated set of 40 galaxies with direct black hole mass measurements gives a consistent result, such that log(Mbh/M⊙) = (8.25± 0.05) + (3.68± 0.25) log[σ/200 km s ]. The (barless) σ-L relation for galaxies with black hole mass measurements is found to be consistent with that from the SDSS sample of early-type galaxies. In addition the barless Mbh-σ relation, the Mbh-n relation, and the Mbh-L relation are shown to yield SMBH masses less than 2-4×10 M⊙. Subject headings: black hole physics — galaxies: bulges — galaxies: fundamental parameters — galaxies: structure