SIMBAD references

In this work we discuss the technique of using molecular gas kinematics (or the kinematics of any dynamically cold tracer) to estimate black hole masses. We present a figure of merit that will be useful in defining future observational campaigns, and discuss its implications. We show that, in principle, one can estimate black hole masses using data that only resolve scales ~2 times the formal black hole sphere of influence, and confirm this by re-analysing lower resolution observations of the molecular gas around the black hole in NGC 4526. We go on to discuss the effect that angular resolution, velocity resolution and the depth of the galaxies potential have on the ability to estimate black hole masses, and conclude by discussing prospects for the future. Once Atacama Large Millimetre/submillimetre Array is fully operational, we find that over 105 local galaxies with massive black holes will be observable, and that given sufficient surface brightness sensitivity one could measure the mass of a ≳ 4x10⁸M_☉ black hole at any redshift.