The relation between black hole mass and velocity dispersion at z ∼ 0.37

The velocity dispersion of seven Seyfert 1 galaxies at z similar to 0.37 is measured using high signal-to-noise ratio Keck spectra. Black hole ( BH) mass estimates are obtained via an empirically calibrated photoionization method. We derive the BH mass velocity dispersion relationship at z similar to 0.37. We find an offset with respect to the local relationship, in the sense of somewhat lower velocity dispersion at a fixed BH mass at than today, which is significant at the 97% level. The offset corresponds to Delta log sigma = -0.16, with an rms scatter of 0.13 dex. If confirmed by larger samples and independent checks on systematic uncertainties and selection effects, this result would be consistent with spheroids evolving faster than BHs in the past 4 Gyr and inconsistent with pure luminosity evolution.