z<0.4 sources from Chandra/SDSS

XRB spectral states show a V-shaped correlation between X-ray spectral hardness and Eddington ratio as they vary, and some AGN samples reveal a similar trend, implying analogous processes at vastly larger masses and timescales. To further investigate the analogies, we have matched 617 sources from the Chandra Source Catalog (CSC) to Sloan Digital Sky Survey (SDSS) spectroscopy, and uniformly measured both X-ray and optical spectral characteristics across a broad range of AGN and galaxy types.

We provide useful tabulations of X-ray spectral slope for broad- and narrow-line AGNs, star-forming and passive galaxies, and composite systems, also updating relationships between optical (H{alpha} and [OIII]) line emission and X-ray luminosity. We further fit broadband spectral energy distributions with a variety of templates to estimate bolometric luminosity. Our results confirm a significant trend in AGNs between X-ray spectral hardness and Eddington ratio expressed in X-ray luminosity, albeit with significant dispersion.