High-redshift quasars in the Cold Dark Matter cosmogony
Open Access
- 1 January 1988
- journal article
- Published by Oxford University Press (OUP) in Monthly Notices of the Royal Astronomical Society
- Vol. 230 (1) , 5P-11P
- https://doi.org/10.1093/mnras/230.1.5p
Abstract
We investigate the relationship between high-redshift quasars and the epoch of galaxy formation in the Cold Dark Matter (CDM) cosmogony. Luminous quasars could only form after galactic sized systems had collapsed. A constant comoving density of luminous quasars between z = 2 and z = 4 is compatible with the CDM model if quasars are short-lived and radiate at about the Eddington limit. However, according to the CDM model the abundance of high-luminosity quasars must decline exponentially at higher redshifts. Even if all protogalaxies form quasars, and about 1 per cent of the baryons within a protogalaxy collapse into a compact object, we would expect a steep fall in the density of quasars with L>1047 erg s−1 at redshifts z≳5. The existence of a ‘cut-off’ in the quasar numbers at high redshift could therefore supply an important test of the CDM theory.Keywords
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