Evidence is presented that the central black-holes in distant, luminous quasars must have built up a significant fraction of their mass early and/or fast, that is before the bulk of the stars in their host galaxies.Available spectral data of luminous, high-redshift (1.5 < z <∼6) quasars show their central black-holes to have masses of ∼109 Msol on average. Yet, other studies show that host galaxies of active galaxies and quasars at redshifts beyond 3 are relatively young: they have very high star-formation rates, contain large amounts of molecular gas and dust, but contain only a small fraction of what can be expected to be the final stellar mass of the galaxy. This contribution also summarizes how the high-z black hole masses are estimated and why. The results presented here are discussed in further detail by Vestergaard (2004; hereafter Paper I).
Coevolution of Black Holes and Galaxies
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