Cosmic Evolution of Black Holes and Spheroids. III. The M(BH)- S() Relation in the Last Six Billion Years

We measure the evolution of the correlation between black hole mass and host spheroid velocity dispersion (M(BH)-S(*)) over the last 6 billion years, by studying three carefully selected samples of active galaxies at [image] and [image]. For all three samples, virial black hole masses are consistently estimated using the line dispersion of Hb and the continuum luminosity at 5100 Aa or Ha line luminosity, based on our cross calibration of the broad-line region size-luminosity relation. For the [image] sample, new stellar velocity dispersions are measured from high signal-to-noise ratio spectra obtained at the Keck Telescope, while for the two lower redshift samples they are compiled from previous works. Extending our previous result at [image], we find an offset from the local relation, suggesting that for fixed M(BH), distant spheroids have on average smaller velocity dispersions than local ones. The measured offset at [image] is [image] (or [image]), i.e., [image]. This is inconsistent with a tight and nonevolving universal M(BH)-S(*) relation at the 95% CL.