"Comparing Direct Black Hole Mass Measurements in AGNs"

Supermassive black holes appear to be ubiquitous in the nuclei of massive galaxies, and several large-scale galaxy properties have been to found to scale with black hole mass, giving rise to the idea that galaxies and their black holes likely co-evolve.  There are only a few techniques that can directly constrain the mass of a black hole through its gravitational influence on luminous matter, of which the most commonly applied are reverberation mapping and stellar or gas dynamical modeling.  These techniques have been applied to a modest number of black holes, with the vast majority of black hole masses in the literature instead being estimates derived from scaling relationships that are based on direct measurements.  Dynamical modeling results provide most commonly used scaling relationships for galaxies in the local universe, while outside the local universe, reverberation mapping results provide the foundation for AGN scaling relationships.   Thus there are two different mass scales currently in use.  Only a handful of black holes have masses that have been constrained through multiple techniques because of their disparate technical requirements.  In AGNs, the situation is even worse because active galaxies are rare and most are too far away to allow the spatial resolution needed for dynamical modeling.  I will describe our ongoing project to directly compare black hole masses from reverberation mapping and stellar dynamical modeling in the nearest Type 1 Seyferts.  Both reverberation mapping and stellar dynamical modeling are time- and resource-intensive techniques and the number of galaxies we can study is small, but the results will help uncover potential biases in these direct mass techniques and illuminate any differences in the black hole mass scales that are applied locally versus at cosmological distances.