A quintet of black hole mass determinations

We report five new measurements of central black hole masses based on Space Telescope Imaging Spectrograph and Wide Field Planetary Camera 2 observations with the Hubble Space Telescope (HST) and on axisymmetric, three-integral, Schwarzschild orbit-library kinematic models. We selected a sample of galaxies within a narrow range in velocity dispersion that cover a range of galaxy parameters (including Hubble type and core/powerlaw surface density profile) where we expected to be able to resolve the galaxy's sphere of influence based on the predicted value of the black hole mass from the M-σ relation. We find masses for the following galaxies: NGC3585,MBH = 3.4+1.5-0.6 ×108 M⊙;NGC3607,MBH = 1.2+0.4 -0.4 ×108 M⊙;NGC4026,MBH = 2.1+0.7-0.4 ×108 M⊙; and NGC 5576, MBH = 1.8+0.3-0.4 × 108 M⊙, all significantly excluding MBH = 0. For NGC 3945, MBH = 9+17 -21 × 106 M⊙, which is significantly below predictions from M-σ and M-L relations and consistent with MBH = 0, though the presence of a double bar in this galaxy may present problems for our axisymmetric code.SCOPUS: ar.j