An Efficient Strategy to Select Targets for Gas-Dynamical Measurements of Black Hole Masses Using the Hubble Space Telescope

摘要

Gas-dynamical studies using the Hubble Space Telescope are an integralcomponent for future progress in the search for massive black holes in galacticnuclei. Here we present an extensive set of gas rotation curves obtained withthe Space Telescope Imaging Spectrograph for the central regions of 23 diskgalaxies. We find that the bulges of randomly selected, nearby spiral and S0galaxies generally do not contain well-defined gaseous disks. Only 15%-20% ofdisk galaxies have regular, symmetric velocity fields useful for dynamicalanalysis. Through comparison of the kinematics with Hubble Space Telescopeimages of the nuclear regions, we show that the probability of success can besignificantly boosted by preselecting objects whose central dust lanes follow awell-ordered, circularly symmetric pattern. The dust morphology can beascertained efficiently by visual inspection of unsharp-masked images.