Testing models of quasar hosts with strong gravitational lensing by quasar hosts

Abstract

We perform a statistical analysis of strong gravitational lensing by quasar hosts of background galaxies, in the two competing models of dark matter haloes of quasars, halo occupation distribution (HOD) and Cen and Safarzadeh (CS) models. Utilizing the BolshoiP simulation, we demonstrate that strong gravitational lensing provides a potentially very powerful test of models of quasar hosting haloes. For quasars at z = 0.5, the lensing probability by quasars of background galaxies in the HOD model is higher than that of the CS model by two orders of magnitude or more for lensing image separations in the range of θ ∼ 1.2-12 arcsec. To observationally test this, we show that, as an example, at the depth of the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) wide field survey and with a quasar sample of 1000 at z = 0.5, the two models can be differentiated at 3σ-4σ confidence level. This observational capability is within the reach of Hyper Suprime Cam (HSC) and WFIRST Survey.