Hilbert, Weyl, and the Philosophy of Mathematics

On the co-evolution of supermassive black holes and their host galaxies since z= 3

“…Further, in this model, under‐weight black holes at high redshifts imply that SMBHs must reach Eddington luminosities, in agreement with the findings of this paper under these conditions. Nevertheless, we feel that the most natural conclusion from our results is that SMBHs and their host galaxies evolve principally together, in proportion to one another, preserving the local relation out to z = 3, in agreement with Jahnke et al (2009), as this would require only mild and plausible evolution in μ with redshift.…”

“…For example, Borys et al (2005) find that SCUBA galaxies have SMBHs which are systematically lower than expected from the local relation for their stellar mass by up to a factor of 50 or so (via Eddington methods), and Alexander et al (2008) also deduce that for SMGs (submillimetre galaxies) SMBHs are also smaller than expected for their host galaxy's mass by a smaller factor of 3 or so (via virial methods). However, Jahnke et al (2009) find that type‐1 AGN galaxies from the COSMOS survey fit closely on to the local M BH – M * slope of Haring & Rix (2004) out to z ∼ 2. Conversely, recent studies by Merloni et al (2010) and Declari et al (2010a,b) using virial estimators of SMBH masses in QSOs both conclude that there is evolution in the local M BH – M * relation with redshift such that M * / M BH was lower at high z , by up to a factor of 7 (Decarli et al 2010a,b) or 3 (Merloni et al 2010) by z = 3.…”