Supermassive black holes in six triaxial galaxies: Insights from SINFONI and MUSE observations

Dynamical modelling can be used to constrain the masses of central black holes, but it is challenging to model massive galaxies because of their complex kinematics. We report six new measurements of supermassive black hole masses of massive early-type galaxies from stellar kinematics, which were extracted from adaptive-optics-assisted SINFONI and MUSE observations. We combined the stellar kinematics with HST photometry to build DYNAMITE triaxial Schwarzschild orbit-superposition models. Our Schwarzschild models can recover the complex triaxial features of the galaxies and constrain the black hole masses of all six galaxies. We found that strong triaxial kinematic features can bias the mass measurements and corrected for this effect. The derived black hole masses are (1.14 −0.63 +0.41 ) × 10 9 M ⊙ for NGC 3706, (1.19 −0.80 +1.34 ) × 10 9 M ⊙ for NGC 3923, (1.14 −0.95 +1.08 ) × 10 9 M ⊙ for NGC 4261, (4.68 −4.26 +2.99 ) × 10 8 M ⊙ for NGC 4636, (3.51 −2.57 +3.37 ) × 10 9 M ⊙ for IC 4296, and (2.43 −1.65 +1.53 ) × 10 9 M ⊙ for IC 4329 at a confidence level of 3 σ . We compared our measurements with published results from axisymmetric Schwarzschild modelling and with our JAM Jeans Anisotropic models and obtained mostly consistent black hole masses. Most of our black hole mass estimates can be well constrained using MUSE observations alone. All of our mass measurements agree with local black hole scaling relations.