As a part of the mm-Wave Interferometric Survey of Dark Object Masses ( WISDOM ) project , we present an estimate of the mass of the supermassive black hole ( SMBH ) in the nearby fast-rotator early-type galaxy NGC 3665 .
We obtained Combined Array for Research in Millimeter Astronomy ( CARMA ) B and C array observations of the ^ { 12 } CO ( J = 2 - 1 ) emission line with a combined angular resolution of 0 \farcs 59 .
We analysed and modelled the three-dimensional molecular gas kinematics , obtaining a best-fit SMBH mass M _ { BH } = 5.75 ^ { +1.49 } _ { -1.18 } \times 10 ^ { 8 } M _ { \odot } , a mass-to-light ratio at H -band ( M / L ) _ { H } = 1.45 \pm 0.04 ( M / L ) _ { \odot,H } , and other parameters describing the geometry of the molecular gas disc ( statistical errors , all at 3 \sigma confidence ) .
We estimate the systematic uncertainties on the stellar M / L to be \approx 0.2 ( M / L ) _ { \odot,H } , and on the SMBH mass to be \approx 0.4 \times 10 ^ { 8 } M _ { \odot } .
The measured SMBH mass is consistent with that estimated from the latest correlations with galaxy properties .
Following our older works , we also analysed and modelled the kinematics using only the major-axis position-velocity diagram , and conclude that the two methods are consistent .