OPTICAL SPECTRAL PROPERTIES OF SWIFT BURST ALERT TELESCOPE HARD X-RAY-SELECTED ACTIVE GALACTIC NUCLEI SOURCES

The Swift Burst Alert Telescope survey of active galactic nuclei (AGNs) is providing an unprecedented view of local AGNs (< z > approximate to 0.03) and their host galaxy properties. In this paper, we present an analysis of the optical spectra of a sample of 64 AGNs from the nine month survey, detected solely based on their 14-195 keV flux. Our analysis includes both archived spectra from the Sloan Digital Sky Survey and our own observations from the 2.1 m Kitt Peak National Observatory telescope. Among our results, we include line ratio classifications utilizing standard emission line diagnostic plots, [O III] 5007 angstrom luminosities, and H beta-derived black hole masses. As in our X-ray study, we find the type 2 sources to be less luminous (in [O III] 5007 angstrom and 14-195 keV luminosities) with lower accretion rates than the type 1 sources. We find that the optically classified low-ionization narrow emission line regions, H II/composite galaxies, and ambiguous sources have the lowest luminosities, while both broad-line and narrow-line Seyferts have similar luminosities. From a comparison of the hard X-ray (14-195 keV) and [O III] luminosities, we find that both the observed and extinction-corrected [O III] luminosities are weakly correlated with X-ray luminosity. In a study of the host galaxy properties from both continuum fits and measurements of the stellar absorption indices, we find that the hosts of the narrow-line sources have properties consistent with late-type galaxies.