Program: GN-2011B-Q-97

Black hole masses for samples of active galactic nuclei (AGN) are currently estimated from single-epoch optical spectra. In particular, the two quantities needed for a black hole mass calculation, namely, the velocity and the radial distance of the orbiting material are derived from the widths of the Balmer hydrogen broad emission lines and the optical continuum luminosity, respectively. However, this method has non-negligible problems: the optical continuum is often heavily contaminated by host galaxy starlight and so without accurate correction is not a good measure of the incident ionizing flux, the optical hydrogen broad emission lines are blended with other species (such as Fe II), and optical measures can suffer from dust extinction. We have recently found a near-IR relationship for estimating AGN black hole masses that circumvents these problems. It is based on the widths of the Paschen hydrogen broad emission lines and the 1-micron continuum luminosity. Here we propose to measure these two quantities with GNIRS in 12 AGN with reverberation-based black hole masses. The observations will considerably improve the number statistics and reduce the scatter in our relationship.