Properties of high-redshift quasars - I. Evolution of the supermassive black hole to halo mass ratio

Abstract

In the local Universe, the masses of supermassive black holes (SMBHs) appear to correlate with the physical properties of their hosts, including the mass of the dark matter haloes. At higher redshifts, we observe the growth of SMBHs indirectly through the identification of high-redshift quasars. However, information on their hosts is more difficult to obtain. In this paper, we determine the masses of the haloes that host the high-redshift quasars (at z > 4) by comparing the rate of growth of quasar density with that predicted by the Press-Schechter mass function. The host mass determined depends on how the ratio between the SMBH and the host halo mass evolves with redshift. Under the assumpt..