Cosmic evolution of black holes and spheroids.: III.: The MBH-σ* 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-sigma(*)) over the last 6 billion years, by studying three carefully selected samples of active galaxies at z = 0.57, z = 0.36 and z < 0.1. For all three samples, virial black hole masses are consistently estimated using the line dispersion of H beta and the continuum luminosity at 5100 angstrom or H alpha line luminosity, based on our cross calibration of the broad-line region size-luminosity relation. For the z 0: 57 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 z 0: 36, 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 z = 0.57 is Delta log sigma(*) = 0.12 +/- 0.05 +/- 0.06 (or Delta log M-BH = 0.50 +/- 0.22 +/- 0.25), i.e., Delta logM(BH) = (3.1 +/- 1.5) log (1 + z) + 0.05 + 0.21. This is inconsistent with a tight and nonevolving universal M-BH-sigma(*) relation at the 95% CL.