Cosmic Evolution of Black Holes and Spheroids. II. Scaling Relations atz = 0.36

We combine Hubble Space Telescope images of a sample of 20 Seyfert galaxies at z=0. 36 with spectroscopic information from the Keck Telescope to determine the black hole mass - spheroid luminosity relation (M-L), the Fundamental Plane (FP) of the host galaxies and the M-sigma relation. Assuming pure luminosity evolution, we find that the host spheroids had smaller luminosity and stellar velocity dispersion than today for a fixed M. The offsets correspond to Delta log LB, 0=0. 40+-0. 11+-0. 15 (Delta log M = 0. 51+-0. 14+-0. 19) and Delta log sigma = 0. 13+-0. 03+-0. 05 (Delta log M = 0. 54+-0. 12+-0. 21), respectively for the M-L and M-sigma relation. A detailed analysis of known systematic errors and selection effects shows that they cannot account for the observed offset. The data are inconsistent with pure luminosity evolution and the existence of universal and tight scaling relations. To obey the three local scaling relations by z=0 the distant spheroids have to grow their stellar mass by approximately 60% (log Mₛph=0. 20+-0. 14) in the next 4 billion years. The measured evolution can be expressed as M/ Mₛph ~ (1+z) ^1. 5+-1. 0. Based on the disturbed morphologies of a fraction of the sample (6/20) we suggest collisional mergers with disk-dominated systems as evolutionary mechanism.