The goal of the BASS sample is to obtain emission line measurements, black hole masses, and high-quality X-ray observations for a large sample (~1000) of the brightest and most powerful hard X-ray selected AGN (>10 keV) on the sky. The hard X-ray selection ensures a sample that includes both unobscured and the dusty and heavily obscured AGN that are only found in the high energy X-rays (>10 keV). In the first data release, we use the largest available optical spectroscopic sample of Swift BAT sources using dedicated observations and public archival data for a sample of 641 unique AGN with spectra that are flux and wavelength calibrated and the spectral resolution was well determined.
We performed three separate sets of spectral measurements with the 641 BASS spectra. In the first step, each AGN host galaxy was fit using galaxy stellar templates and the velocity dispersion was measured when possible. The emission lines were then fit using narrow components and broad components when needed. Black hole masses in AGN with broad emission lines were measured by a more detailed fit to the spectral regions that include the broad Hβ and/or broad Hα lines, or the MgIIλ2798 and CIVλ1549 lines in high redshift sources. Finally, we estimated the bolometric luminosity (Lbol) from the X-ray luminosity to estimate the accretion rates.