Do all QSOs have the same black hole mass?

TL;DR

This study investigates whether all QSOs share similar black hole masses by analyzing clustering data across different redshifts, suggesting a narrow range of host halo and black hole masses and implications for QSO evolution models.

Contribution

It provides evidence that QSOs may have a relatively narrow range of black hole and halo masses, challenging models where QSOs radiate at Eddington luminosity and highlighting the importance of clustering data in understanding QSO evolution.

Findings

QSOs exhibit similar clustering amplitudes across luminosities at fixed redshift.

QSO clustering evolution suggests a fixed host halo and black hole mass over time.

Inclusion of low-redshift data supports long-lived QSO models.

Abstract

QSOs from SDSS, 2QZ and 2SLAQ covering an order of magnitude in luminosity at fixed redshift exhibit similar amplitudes of clustering. In addition, QSO clustering evolution at z>0.5 is well fitted by a model that assumes a fixed host halo mass, implying that QSOs may occur in a relatively narrow range of halo and BH mass. We argue that the slow evolution of early-type galaxies out to z~1-2 may also provide support for a slow evolution of QSO host BH masses. The result would mean that if high-z QSOs radiate at Eddington rates then low-z SyI must radiate at ~100x less than Eddington. We conclude that models where QSOs radiate at L_Edd require M_BH and M_halo to be decoupled to circumvent the clustering results. While single BH mass and flickering models fit the z>0.5 clustering results, they appear to be rejected by the z~0, M_BH-L relation from reverberation mapping. We find that the inclusion of z<0.5 QSO clustering data improves the fit of a long-lived QSO model and suggest that the predictions of a PLE model for QSO BH masses agree reasonably with UV-bump and reverberation estimates (abridged).