WISDOM project - VII. Molecular gas measurement of the supermassive black hole mass in the elliptical galaxy NGC 7052

Supermassive black hole (SMBH) masses can be measured by resolving the dynamical influences of the SMBHs on tracers of the central potentials. Modern long-baseline interferometers have enabled the use of molecular gas as such a tracer. We present here Atacama Large Millimeter/submillimeter Array observations of the elliptical galaxy NGC 7052 at 0.''.11 (37 pc) resolution in the (CO)-C-12(2-1) line and 1.3 mm continuum emission. This resolution is sufficient to resolve the region in which the potential is dominated by the SMBH. We forward model these observations, using a multi-Gaussian expansion of a Hubble Space Telescope F814W image and a spatially constant mass-to-light ratio to model the stellar mass distribution. We infer an SMBH mass of 2.5 +/- 0.3 x 10(9) M-circle dot and a stellar I-band mass-to-light ratio of 4.6 +/- 0.2 M-circle dot/L-circle dot,L-I (3 sigma confidence intervals). This SMBH mass is significantly larger than that derived using ionized gas kinematics, which however appears significantly more kinematically disturbed than the molecular gas. We also show that a central molecular gas deficit is likely to be the result of tidal disruption of molecular gas clouds due to the strong gradient in the central gravitational potential.

Automated summary

Using observations from the Atacama Large Millimeter/submillimeter Array, researchers were able to determine the mass of the SMBH and the stellar mass-to-light ratio in the elliptical galaxy NGC 7052. The results showed that the SMBH mass was significantly larger than previously estimated using ionized gas kinematics, and a central molecular gas deficit was likely due to tidal disruption.