The supermassive black hole in NGC4486a detected with SINFONI at the very large telescope

The near-infrared (IR) integral field spectrograph SINFONI at the European Southern Observatory Very Large Telescope opens a new window for the study of central supermassive black holes. With a near-IR spatial resolution similar to Hubble Space Telescope optical and the ability to penetrate dust, it provides the possibility to explore the low-mass end of the M-center dot-sigma relation (sigma < 120 km s(-1)) where so far very few black hole masses were measured with stellar dynamics. With SINFONI, we observed the central region of the low-luminosity elliptical galaxy NGC 4486a at a spatial resolution of approximate to 0.1 arcsec in the K band. The stellar kinematics were measured with a maximum penalized likelihood method considering the region around the CO absorption band heads. We determined a black hole mass of M-center dot = (1.25(-0.79)(+0.75)) x 10(7) M-circle dot (90 per cent confidence limit) using the Schwarzschild orbit superposition method including the full two-dimensional spatial information. This mass agrees with the predictions of the M-center dot-sigma relation, strengthening its validity at the lower sigma end.